Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

5 files changed, 4299 insertions, 0 deletions

diff --git a/third_party/rust/qlog/.cargo-checksum.json b/third_party/rust/qlog/.cargo-checksum.json
new file mode 100644
index 0000000000..f0db87c5fe
--- /dev/null
+++ b/third_party/rust/qlog/.cargo-checksum.json
@@ -0,0 +1 @@
+{"files":{"Cargo.toml":"3e92e34343c4777cb0249185b1f693a2e21321b090136be6d5287cadf353db1c","README.md":"c74fdbabf7262695e42a9af0b8c0c2f089c188dde8b13bc71847551f126397b4","src/event.rs":"866b2cb41af83e1552dd10ae8e07a9ae40b65bd8ca63c10537b38e9be0abfe3c","src/lib.rs":"c557479cf4c1f6c44c3fd708338eebe5fb2e01f106259db58578a9a1b55ef358"},"package":"8777d5490145d6907198d48b3a907447689ce80e071b3d8a16a9d9fb3df02bc1"}
\ No newline at end of file
diff --git a/third_party/rust/qlog/Cargo.toml b/third_party/rust/qlog/Cargo.toml
new file mode 100644
index 0000000000..a1304cd9ab
--- /dev/null
+++ b/third_party/rust/qlog/Cargo.toml
@@ -0,0 +1,36 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies
+#
+# If you believe there's an error in this file please file an
+# issue against the rust-lang/cargo repository. If you're
+# editing this file be aware that the upstream Cargo.toml
+# will likely look very different (and much more reasonable)
+
+[package]
+edition = "2018"
+name = "qlog"
+version = "0.4.0"
+authors = ["Lucas Pardue <lucaspardue.24.7@gmail.com>"]
+description = "qlog data model for QUIC and HTTP/3"
+readme = "README.md"
+keywords = ["qlog", "quic", "http3"]
+categories = ["network-programming"]
+license = "BSD-2-Clause"
+repository = "https://github.com/cloudflare/quiche"
+[dependencies.serde]
+version = "1"
+features = ["derive"]
+
+[dependencies.serde_derive]
+version = "1.0"
+
+[dependencies.serde_json]
+version = "1.0"
+features = ["preserve_order"]
+
+[dependencies.serde_with]
+version = "1.3.1"
diff --git a/third_party/rust/qlog/README.md b/third_party/rust/qlog/README.md
new file mode 100644
index 0000000000..cc420a17d7
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+++ b/third_party/rust/qlog/README.md
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+The qlog crate is an implementation of the [qlog main schema] and [qlog QUIC and
+HTTP/3 events] that attempts to closely follow the format of the qlog
+[TypeScript schema]. This is just a data model and no support is provided for
+logging IO, applications can decide themselves the most appropriate method.
+
+The crate uses Serde for conversion between Rust and JSON.
+
+[qlog main schema]: https://tools.ietf.org/html/draft-marx-qlog-main-schema
+[qlog QUIC and HTTP/3 events]: https://quiclog.github.io/internet-drafts/draft-marx-qlog-event-definitions-quic-h3
+[TypeScript schema]: https://github.com/quiclog/qlog/blob/master/TypeScript/draft-01/QLog.ts
+
+Overview
+--------
+qlog is a hierarchical logging format, with a rough structure of:
+
+* Log
+  * Trace(s)
+    * Event(s)
+
+In practice, a single QUIC connection maps to a single Trace file with one
+or more Events. Applications can decide whether to combine Traces from
+different connections into the same Log.
+
+## Traces
+
+A [`Trace`] contains metadata such as the [`VantagePoint`] of capture and
+the [`Configuration`] of the `Trace`.
+
+A very important part of the `Trace` is the definition of `event_fields`. A
+qlog Event is a vector of [`EventField`]; this provides great flexibility to
+log events with any number of `EventFields` in any order. The `event_fields`
+property describes the format of event logging and it is important that
+events comply with that format. Failing to do so it going to cause problems
+for qlog analysis tools. For information is available at
+https://tools.ietf.org/html/draft-marx-qlog-main-schema-01#section-3.3.4
+
+In order to make using qlog a bit easier, this crate expects a qlog Event to
+consist of the following EventFields in the following order:
+[`EventField::RelativeTime`], [`EventField::Category`],
+[`EventField::Event`] and [`EventField::Data`]. A set of methods are
+provided to assist in creating a Trace and appending events to it in this
+format.
+
+## Writing out logs
+As events occur during the connection, the application appends them to the
+trace. The qlog crate supports two modes of writing logs: the buffered mode
+stores everything in memory and requires the application to serialize and write
+the output, the streaming mode progressively writes serialized JSON output to a
+writer designated by the application.
+
+Buffered Mode
+---------------
+
+Create the trace:
+
+```rust
+let mut trace = qlog::Trace::new(
+    qlog::VantagePoint {
+        name: Some("Example client".to_string()),
+        ty: qlog::VantagePointType::Client,
+        flow: None,
+    },
+    Some("Example qlog trace".to_string()),
+    Some("Example qlog trace description".to_string()),
+    Some(qlog::Configuration {
+        time_offset: Some("0".to_string()),
+        time_units: Some(qlog::TimeUnits::Ms),
+        original_uris: None,
+    }),
+    None,
+);
+```
+
+### Adding events
+
+Qlog Events are added to `qlog::Trace.events`.
+
+It is recommended to use the provided utility methods to append semantically
+valid events to a trace. However, there is nothing preventing you from
+creating the events manually.
+
+The following example demonstrates how to log a QUIC packet
+containing a single Crypto frame. It uses the [`QuicFrame::crypto()`],
+[`packet_sent_min()`] and [`push_event()`] methods to create and log a
+PacketSent event and its EventData.
+
+```rust
+let scid = [0x7e, 0x37, 0xe4, 0xdc, 0xc6, 0x68, 0x2d, 0xa8];
+let dcid = [0x36, 0xce, 0x10, 0x4e, 0xee, 0x50, 0x10, 0x1c];
+
+let pkt_hdr = qlog::PacketHeader::new(
+    0,
+    Some(1251),
+    Some(1224),
+    Some(0xff00001b),
+    Some(b"7e37e4dcc6682da8"),
+    Some(&dcid),
+);
+
+let frames =
+    vec![qlog::QuicFrame::crypto("0".to_string(), "1000".to_string())];
+
+let event = qlog::event::Event::packet_sent_min(
+    qlog::PacketType::Initial,
+    pkt_hdr,
+    Some(frames),
+);
+
+trace.push_event(std::time::Duration::new(0, 0), event);
+```
+
+### Serializing
+
+The qlog crate has only been tested with `serde_json`, however other serializer
+targets might work.
+
+For example, serializing the trace created above:
+
+```rust
+serde_json::to_string_pretty(&trace).unwrap();
+```
+
+would generate the following:
+
+```
+{
+  "vantage_point": {
+    "name": "Example client",
+    "type": "client"
+  },
+  "title": "Example qlog trace",
+  "description": "Example qlog trace description",
+  "configuration": {
+    "time_units": "ms",
+    "time_offset": "0"
+  },
+  "event_fields": [
+    "relative_time",
+    "category",
+    "event",
+    "data"
+  ],
+  "events": [
+    [
+      "0",
+      "transport",
+      "packet_sent",
+      {
+        "packet_type": "initial",
+        "header": {
+          "packet_number": "0",
+          "packet_size": 1251,
+          "payload_length": 1224,
+          "version": "0xff00001b",
+          "scil": "8",
+          "dcil": "8",
+          "scid": "7e37e4dcc6682da8",
+          "dcid": "36ce104eee50101c"
+        },
+        "frames": [
+          {
+            "frame_type": "crypto",
+            "offset": "0",
+            "length": "100",
+          }
+        ]
+      }
+    ]
+  ]
+}
+```
+
+Streaming Mode
+---------------
+
+Create the trace:
+
+```rust
+let mut trace = qlog::Trace::new(
+    qlog::VantagePoint {
+        name: Some("Example client".to_string()),
+        ty: qlog::VantagePointType::Client,
+        flow: None,
+    },
+    Some("Example qlog trace".to_string()),
+    Some("Example qlog trace description".to_string()),
+    Some(qlog::Configuration {
+        time_offset: Some("0".to_string()),
+        time_units: Some(qlog::TimeUnits::Ms),
+        original_uris: None,
+    }),
+    None,
+);
+```
+
+Create an object with the [`Write`] trait:
+
+```rust
+let mut file = std::fs::File::create("foo.qlog").unwrap();
+```
+
+Create a [`QlogStreamer`] and start serialization to foo.qlog
+using [`start_log()`]:
+
+```rust
+let mut streamer = qlog::QlogStreamer::new(
+    qlog::QLOG_VERSION.to_string(),
+    Some("Example qlog".to_string()),
+    Some("Example qlog description".to_string()),
+    None,
+    std::time::Instant::now(),
+    trace,
+    Box::new(file),
+);
+
+streamer.start_log().ok();
+
+```
+
+### Adding simple events
+
+Once logging has started you can stream events. Simple events can be written in
+one step using [`add_event()`]:
+
+```rust
+let event = qlog::event::Event::metrics_updated_min();
+streamer.add_event(event).ok();
+```
+
+### Adding events with frames
+Some events contain optional arrays of QUIC frames. If the event has
+`Some(Vec<QuicFrame>)`, even if it is empty, the streamer enters a frame
+serializing mode that must be finalized before other events can be logged.
+
+In this example, a PacketSent event is created with an empty frame array and
+frames are written out later:
+
+```rust
+let qlog_pkt_hdr = qlog::PacketHeader::with_type(
+    qlog::PacketType::OneRtt,
+    0,
+    Some(1251),
+    Some(1224),
+    Some(0xff00001b),
+    Some(b"7e37e4dcc6682da8"),
+    Some(b"36ce104eee50101c"),
+);
+
+let event = qlog::event::Event::packet_sent_min(
+    qlog::PacketType::OneRtt,
+    qlog_pkt_hdr,
+    Some(Vec::new()),
+);
+
+streamer.add_event(event).ok();
+
+```
+
+In this example, the frames contained in the QUIC packet
+are PING and PADDING. Each frame is written using the
+[`add_frame()`] method. Frame writing is concluded with
+[`finish_frames()`].
+
+```rust
+let ping = qlog::QuicFrame::ping();
+let padding = qlog::QuicFrame::padding();
+
+streamer.add_frame(ping, false).ok();
+streamer.add_frame(padding, false).ok();
+
+streamer.finish_frames().ok();
+```
+
+Once all events have have been written, the log
+can be finalized with [`finish_log()`]:
+
+```rust
+streamer.finish_log().ok();
+```
+
+### Serializing
+
+Serialization to JSON occurs as methods on the [`QlogStreamer`]
+are called. No additional steps are required.
+
+[`Trace`]: struct.Trace.html
+[`VantagePoint`]: struct.VantagePoint.html
+[`Configuration`]: struct.Configuration.html
+[`EventField`]: enum.EventField.html
+[`EventField::RelativeTime`]: enum.EventField.html#variant.RelativeTime
+[`EventField::Category`]: enum.EventField.html#variant.Category
+[`EventField::Type`]: enum.EventField.html#variant.Type
+[`EventField::Data`]: enum.EventField.html#variant.Data
+[`qlog::Trace.events`]: struct.Trace.html#structfield.events
+[`push_event()`]: struct.Trace.html#method.push_event
+[`packet_sent_min()`]: event/struct.Event.html#method.packet_sent_min
+[`QuicFrame::crypto()`]: enum.QuicFrame.html#variant.Crypto
+[`QlogStreamer`]: struct.QlogStreamer.html
+[`Write`]: https://doc.rust-lang.org/std/io/trait.Write.html
+[`start_log()`]: struct.QlogStreamer.html#method.start_log
+[`add_event()`]: struct.QlogStreamer.html#method.add_event
+[`add_frame()`]: struct.QlogStreamer.html#method.add_frame
+[`finish_frames()`]: struct.QlogStreamer.html#method.finish_frames
+[`finish_log()`]: struct.QlogStreamer.html#method.finish_log
\ No newline at end of file
diff --git a/third_party/rust/qlog/src/event.rs b/third_party/rust/qlog/src/event.rs
new file mode 100644
index 0000000000..5748bf82d5
--- /dev/null
+++ b/third_party/rust/qlog/src/event.rs
@@ -0,0 +1,988 @@
+// Copyright (C) 2020, Cloudflare, Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright notice,
+//       this list of conditions and the following disclaimer.
+//
+//     * Redistributions in binary form must reproduce the above copyright
+//       notice, this list of conditions and the following disclaimer in the
+//       documentation and/or other materials provided with the distribution.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+// IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+//! Module-defined Event and functions to work with qlog data structures.
+//!
+//! The Qlog data structures are very flexible, which makes working with them
+//! liable to simple semantic errors. This module provides some helper functions
+//! that focus on creating valid types, while also reducing some of the
+//! verbosity of using the raw data structures.
+
+use super::*;
+
+/// A representation of qlog events that couple EventCategory, EventType and
+/// EventData.
+///
+/// Functions are provided to help construct valid events. Most events consist
+/// of several optional fields, so minimal versions of these functions are
+/// provided, which accept only mandatory qlog parameters. Minimal functions are
+/// identified by a `_min` suffix.
+#[derive(Clone)]
+pub struct Event {
+    pub category: EventCategory,
+    pub ty: EventType,
+    pub data: EventData,
+}
+
+#[allow(clippy::too_many_arguments)]
+impl Event {
+    // Connectivity events.
+
+    /// Returns:
+    /// * `EventCategory`=`Connectivity`
+    /// * `EventType`=`ConnectivityEventType::ServerListening`
+    /// * `EventData`=`ServerListening`.
+    pub fn server_listening(
+        ip_v4: Option<String>, ip_v6: Option<String>, port_v4: u64, port_v6: u64,
+        quic_versions: Option<Vec<String>>, alpn_values: Option<Vec<String>>,
+        stateless_reset_required: Option<bool>,
+    ) -> Self {
+        Event {
+            category: EventCategory::Connectivity,
+            ty: EventType::ConnectivityEventType(
+                ConnectivityEventType::ServerListening,
+            ),
+            data: EventData::ServerListening {
+                ip_v4,
+                ip_v6,
+                port_v4,
+                port_v6,
+                quic_versions,
+                alpn_values,
+                stateless_reset_required,
+            },
+        }
+    }
+
+    pub fn server_listening_min(port_v4: u64, port_v6: u64) -> Self {
+        Event::server_listening(None, None, port_v4, port_v6, None, None, None)
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Connectivity`
+    /// * `EventType`=`ConnectivityEventType::ConnectionStarted`
+    /// * `EventData`=`ConnectionStarted`.
+    pub fn connection_started(
+        ip_version: String, src_ip: String, dst_ip: String,
+        protocol: Option<String>, src_port: u64, dst_port: u64,
+        quic_version: Option<String>, src_cid: Option<String>,
+        dst_cid: Option<String>,
+    ) -> Self {
+        Event {
+            category: EventCategory::Connectivity,
+            ty: EventType::ConnectivityEventType(
+                ConnectivityEventType::ConnectionStarted,
+            ),
+            data: EventData::ConnectionStarted {
+                ip_version,
+                src_ip,
+                dst_ip,
+                protocol,
+                src_port,
+                dst_port,
+                quic_version,
+                src_cid,
+                dst_cid,
+            },
+        }
+    }
+
+    pub fn connection_started_min(
+        ip_version: String, src_ip: String, dst_ip: String, src_port: u64,
+        dst_port: u64,
+    ) -> Self {
+        Event::connection_started(
+            ip_version, src_ip, dst_ip, None, src_port, dst_port, None, None,
+            None,
+        )
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Connectivity`
+    /// * `EventType`=`ConnectivityEventType::ConnectionIdUpdated`
+    /// * `EventData`=`ConnectionIdUpdated`.
+    pub fn connection_id_updated(
+        src_old: Option<String>, src_new: Option<String>,
+        dst_old: Option<String>, dst_new: Option<String>,
+    ) -> Self {
+        Event {
+            category: EventCategory::Connectivity,
+            ty: EventType::ConnectivityEventType(
+                ConnectivityEventType::ConnectionIdUpdated,
+            ),
+            data: EventData::ConnectionIdUpdated {
+                src_old,
+                src_new,
+                dst_old,
+                dst_new,
+            },
+        }
+    }
+
+    pub fn connection_id_updated_min() -> Self {
+        Event::connection_id_updated(None, None, None, None)
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Connectivity`
+    /// * `EventType`=`ConnectivityEventType::SpinBitUpdated`
+    /// * `EventData`=`SpinBitUpdated`.
+    pub fn spinbit_updated(state: bool) -> Self {
+        Event {
+            category: EventCategory::Connectivity,
+            ty: EventType::ConnectivityEventType(
+                ConnectivityEventType::SpinBitUpdated,
+            ),
+            data: EventData::SpinBitUpdated { state },
+        }
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Connectivity`
+    /// * `EventType`=`ConnectivityEventType::ConnectionState`
+    /// * `EventData`=`ConnectionState`.
+    pub fn connection_state_updated(
+        old: Option<ConnectionState>, new: ConnectionState,
+    ) -> Self {
+        Event {
+            category: EventCategory::Connectivity,
+            ty: EventType::ConnectivityEventType(
+                ConnectivityEventType::ConnectionStateUpdated,
+            ),
+            data: EventData::ConnectionStateUpdated { old, new },
+        }
+    }
+
+    pub fn connection_state_updated_min(new: ConnectionState) -> Self {
+        Event::connection_state_updated(None, new)
+    }
+
+    // Transport events.
+
+    /// Returns:
+    /// * `EventCategory`=`Transport`
+    /// * `EventType`=`TransportEventType::ParametersSet`
+    /// * `EventData`=`ParametersSet`.
+    pub fn transport_parameters_set(
+        owner: Option<TransportOwner>, resumption_allowed: Option<bool>,
+        early_data_enabled: Option<bool>, alpn: Option<String>,
+        version: Option<String>, tls_cipher: Option<String>,
+        original_connection_id: Option<String>,
+        stateless_reset_token: Option<String>,
+        disable_active_migration: Option<bool>, idle_timeout: Option<u64>,
+        max_packet_size: Option<u64>, ack_delay_exponent: Option<u64>,
+        max_ack_delay: Option<u64>, active_connection_id_limit: Option<u64>,
+        initial_max_data: Option<String>,
+        initial_max_stream_data_bidi_local: Option<String>,
+        initial_max_stream_data_bidi_remote: Option<String>,
+        initial_max_stream_data_uni: Option<String>,
+        initial_max_streams_bidi: Option<String>,
+        initial_max_streams_uni: Option<String>,
+        preferred_address: Option<PreferredAddress>,
+    ) -> Self {
+        Event {
+            category: EventCategory::Transport,
+            ty: EventType::TransportEventType(TransportEventType::ParametersSet),
+            data: EventData::TransportParametersSet {
+                owner,
+
+                resumption_allowed,
+                early_data_enabled,
+                alpn,
+                version,
+                tls_cipher,
+
+                original_connection_id,
+                stateless_reset_token,
+                disable_active_migration,
+
+                idle_timeout,
+                max_packet_size,
+                ack_delay_exponent,
+                max_ack_delay,
+                active_connection_id_limit,
+
+                initial_max_data,
+                initial_max_stream_data_bidi_local,
+                initial_max_stream_data_bidi_remote,
+                initial_max_stream_data_uni,
+                initial_max_streams_bidi,
+                initial_max_streams_uni,
+
+                preferred_address,
+            },
+        }
+    }
+
+    pub fn transport_parameters_set_min() -> Self {
+        Event::transport_parameters_set(
+            None, None, None, None, None, None, None, None, None, None, None,
+            None, None, None, None, None, None, None, None, None, None,
+        )
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Transport`
+    /// * `EventType`=`TransportEventType::DatagramsReceived`
+    /// * `EventData`=`DatagramsReceived`.
+    pub fn datagrams_received(
+        count: Option<u64>, byte_length: Option<u64>,
+    ) -> Self {
+        Event {
+            category: EventCategory::Transport,
+            ty: EventType::TransportEventType(
+                TransportEventType::DatagramsReceived,
+            ),
+            data: EventData::DatagramsReceived { count, byte_length },
+        }
+    }
+
+    pub fn datagrams_received_min() -> Self {
+        Event::datagrams_received(None, None)
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Transport`
+    /// * `EventType`=`TransportEventType::DatagramsSent`
+    /// * `EventData`=`DatagramsSent`.
+    pub fn datagrams_sent(count: Option<u64>, byte_length: Option<u64>) -> Self {
+        Event {
+            category: EventCategory::Transport,
+            ty: EventType::TransportEventType(TransportEventType::DatagramsSent),
+            data: EventData::DatagramsSent { count, byte_length },
+        }
+    }
+
+    pub fn datagrams_sent_min() -> Self {
+        Event::datagrams_sent(None, None)
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Transport`
+    /// * `EventType`=`TransportEventType::DatagramDropped`
+    /// * `EventData`=`DatagramDropped`.
+    pub fn datagram_dropped(byte_length: Option<u64>) -> Self {
+        Event {
+            category: EventCategory::Transport,
+            ty: EventType::TransportEventType(
+                TransportEventType::DatagramDropped,
+            ),
+            data: EventData::DatagramDropped { byte_length },
+        }
+    }
+
+    pub fn datagram_dropped_min() -> Self {
+        Event::datagram_dropped(None)
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Transport`
+    /// * `EventType`=`TransportEventType::PacketReceived`
+    /// * `EventData`=`PacketReceived`.
+    pub fn packet_received(
+        packet_type: PacketType, header: PacketHeader,
+        frames: Option<Vec<QuicFrame>>, is_coalesced: Option<bool>,
+        raw_encrypted: Option<String>, raw_decrypted: Option<String>,
+    ) -> Self {
+        Event {
+            category: EventCategory::Transport,
+            ty: EventType::TransportEventType(TransportEventType::PacketReceived),
+            data: EventData::PacketReceived {
+                packet_type,
+                header,
+                frames,
+
+                is_coalesced,
+
+                raw_encrypted,
+                raw_decrypted,
+            },
+        }
+    }
+
+    pub fn packet_received_min(
+        packet_type: PacketType, header: PacketHeader,
+    ) -> Self {
+        Event::packet_received(packet_type, header, None, None, None, None)
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Transport`
+    /// * `EventType`=`TransportEventType::PacketSent`
+    /// * `EventData`=`PacketSent`.
+    pub fn packet_sent(
+        packet_type: PacketType, header: PacketHeader,
+        frames: Option<Vec<QuicFrame>>, is_coalesced: Option<bool>,
+        raw_encrypted: Option<String>, raw_decrypted: Option<String>,
+    ) -> Self {
+        Event {
+            category: EventCategory::Transport,
+            ty: EventType::TransportEventType(TransportEventType::PacketSent),
+            data: EventData::PacketSent {
+                packet_type,
+                header,
+                frames,
+
+                is_coalesced,
+
+                raw_encrypted,
+                raw_decrypted,
+            },
+        }
+    }
+
+    pub fn packet_sent_min(
+        packet_type: PacketType, header: PacketHeader,
+        frames: Option<Vec<QuicFrame>>,
+    ) -> Self {
+        Event::packet_sent(packet_type, header, frames, None, None, None)
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Transport`
+    /// * `EventType`=`TransportEventType::PacketDropped`
+    /// * `EventData`=`PacketDropped`.
+    pub fn packet_dropped(
+        packet_type: Option<PacketType>, packet_size: Option<u64>,
+        raw: Option<String>,
+    ) -> Self {
+        Event {
+            category: EventCategory::Transport,
+            ty: EventType::TransportEventType(TransportEventType::PacketDropped),
+            data: EventData::PacketDropped {
+                packet_type,
+                packet_size,
+                raw,
+            },
+        }
+    }
+
+    pub fn packet_dropped_min() -> Self {
+        Event::packet_dropped(None, None, None)
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Transport`
+    /// * `EventType`=`TransportEventType::PacketBuffered`
+    /// * `EventData`=`PacketBuffered`.
+    pub fn packet_buffered(
+        packet_type: PacketType, packet_number: String,
+    ) -> Self {
+        Event {
+            category: EventCategory::Transport,
+            ty: EventType::TransportEventType(TransportEventType::PacketBuffered),
+            data: EventData::PacketBuffered {
+                packet_type,
+                packet_number,
+            },
+        }
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Transport`
+    /// * `EventType`=`TransportEventType::StreamStateUpdated`
+    /// * `EventData`=`StreamStateUpdated`.
+    pub fn stream_state_updated(
+        stream_id: String, stream_type: Option<StreamType>,
+        old: Option<StreamState>, new: StreamState,
+        stream_side: Option<StreamSide>,
+    ) -> Self {
+        Event {
+            category: EventCategory::Connectivity,
+            ty: EventType::TransportEventType(
+                TransportEventType::StreamStateUpdated,
+            ),
+            data: EventData::StreamStateUpdated {
+                stream_id,
+                stream_type,
+                old,
+                new,
+                stream_side,
+            },
+        }
+    }
+
+    pub fn stream_state_updated_min(stream_id: String, new: StreamState) -> Self {
+        Event::stream_state_updated(stream_id, None, None, new, None)
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Transport`
+    /// * `EventType`=`TransportEventType::FramesProcessed`
+    /// * `EventData`=`FramesProcessed`.
+    pub fn frames_processed(frames: Vec<QuicFrame>) -> Self {
+        Event {
+            category: EventCategory::Transport,
+            ty: EventType::TransportEventType(
+                TransportEventType::FramesProcessed,
+            ),
+            data: EventData::FramesProcessed { frames },
+        }
+    }
+
+    // Recovery events.
+
+    /// Returns:
+    /// * `EventCategory`=`Recovery`
+    /// * `EventType`=`RecoveryEventType::ParametersSet`
+    /// * `EventData`=`RecoveryParametersSet`.
+    pub fn recovery_parameters_set(
+        reordering_threshold: Option<u64>, time_threshold: Option<u64>,
+        timer_granularity: Option<u64>, initial_rtt: Option<u64>,
+        max_datagram_size: Option<u64>, initial_congestion_window: Option<u64>,
+        minimum_congestion_window: Option<u64>,
+        loss_reduction_factor: Option<u64>,
+        persistent_congestion_threshold: Option<u64>,
+    ) -> Self {
+        Event {
+            category: EventCategory::Recovery,
+            ty: EventType::RecoveryEventType(RecoveryEventType::ParametersSet),
+            data: EventData::RecoveryParametersSet {
+                reordering_threshold,
+                time_threshold,
+                timer_granularity,
+                initial_rtt,
+                max_datagram_size,
+                initial_congestion_window,
+                minimum_congestion_window,
+                loss_reduction_factor,
+                persistent_congestion_threshold,
+            },
+        }
+    }
+
+    pub fn recovery_parameters_set_min() -> Self {
+        Event::recovery_parameters_set(
+            None, None, None, None, None, None, None, None, None,
+        )
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Recovery`
+    /// * `EventType`=`RecoveryEventType::MetricsUpdated`
+    /// * `EventData`=`MetricsUpdated`.
+    pub fn metrics_updated(
+        min_rtt: Option<u64>, smoothed_rtt: Option<u64>, latest_rtt: Option<u64>,
+        rtt_variance: Option<u64>, max_ack_delay: Option<u64>,
+        pto_count: Option<u64>, congestion_window: Option<u64>,
+        bytes_in_flight: Option<u64>, ssthresh: Option<u64>,
+        packets_in_flight: Option<u64>, in_recovery: Option<bool>,
+        pacing_rate: Option<u64>,
+    ) -> Self {
+        Event {
+            category: EventCategory::Recovery,
+            ty: EventType::RecoveryEventType(RecoveryEventType::MetricsUpdated),
+            data: EventData::MetricsUpdated {
+                min_rtt,
+                smoothed_rtt,
+                latest_rtt,
+                rtt_variance,
+                max_ack_delay,
+                pto_count,
+                congestion_window,
+                bytes_in_flight,
+                ssthresh,
+                packets_in_flight,
+                in_recovery,
+                pacing_rate,
+            },
+        }
+    }
+
+    pub fn metrics_updated_min() -> Self {
+        Event::metrics_updated(
+            None, None, None, None, None, None, None, None, None, None, None,
+            None,
+        )
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Recovery`
+    /// * `EventType`=`RecoveryEventType::CongestionStateUpdated`
+    /// * `EventData`=`CongestionStateUpdated`.
+    pub fn congestion_state_updated(old: Option<String>, new: String) -> Self {
+        Event {
+            category: EventCategory::Recovery,
+            ty: EventType::RecoveryEventType(
+                RecoveryEventType::CongestionStateUpdated,
+            ),
+            data: EventData::CongestionStateUpdated { old, new },
+        }
+    }
+
+    pub fn congestion_state_updated_min(new: String) -> Self {
+        Event::congestion_state_updated(None, new)
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Recovery`
+    /// * `EventType`=`RecoveryEventType::LossTimerSet`
+    /// * `EventData`=`LossTimerSet`.
+    pub fn loss_timer_set(
+        timer_type: Option<TimerType>, timeout: Option<String>,
+    ) -> Self {
+        Event {
+            category: EventCategory::Recovery,
+            ty: EventType::RecoveryEventType(RecoveryEventType::LossTimerSet),
+            data: EventData::LossTimerSet {
+                timer_type,
+                timeout,
+            },
+        }
+    }
+
+    pub fn loss_timer_set_min() -> Self {
+        Event::loss_timer_set(None, None)
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Recovery`
+    /// * `EventType`=`RecoveryEventType::PacketLost`
+    /// * `EventData`=`PacketLost`.
+    pub fn packet_lost(
+        packet_type: PacketType, packet_number: String,
+        header: Option<PacketHeader>, frames: Vec<QuicFrame>,
+    ) -> Self {
+        Event {
+            category: EventCategory::Recovery,
+            ty: EventType::RecoveryEventType(RecoveryEventType::PacketLost),
+            data: EventData::PacketLost {
+                packet_type,
+                packet_number,
+                header,
+                frames,
+            },
+        }
+    }
+
+    pub fn packet_lost_min(
+        packet_type: PacketType, packet_number: String, frames: Vec<QuicFrame>,
+    ) -> Self {
+        Event::packet_lost(packet_type, packet_number, None, frames)
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Recovery`
+    /// * `EventType`=`RecoveryEventType::MarkedForRetransmit`
+    /// * `EventData`=`MarkedForRetransmit`.
+    pub fn marked_for_retransmit(frames: Vec<QuicFrame>) -> Self {
+        Event {
+            category: EventCategory::Recovery,
+            ty: EventType::RecoveryEventType(
+                RecoveryEventType::MarkedForRetransmit,
+            ),
+            data: EventData::MarkedForRetransmit { frames },
+        }
+    }
+
+    // HTTP/3 events.
+
+    /// Returns:
+    /// * `EventCategory`=`Http`
+    /// * `EventType`=`Http3EventType::ParametersSet`
+    /// * `EventData`=`H3ParametersSet`.
+    pub fn h3_parameters_set(
+        owner: Option<H3Owner>, max_header_list_size: Option<u64>,
+        max_table_capacity: Option<u64>, blocked_streams_count: Option<u64>,
+        push_allowed: Option<bool>, waits_for_settings: Option<bool>,
+    ) -> Self {
+        Event {
+            category: EventCategory::Http,
+            ty: EventType::Http3EventType(Http3EventType::ParametersSet),
+            data: EventData::H3ParametersSet {
+                owner,
+                max_header_list_size,
+                max_table_capacity,
+                blocked_streams_count,
+                push_allowed,
+                waits_for_settings,
+            },
+        }
+    }
+
+    pub fn h3_parameters_set_min() -> Self {
+        Event::h3_parameters_set(None, None, None, None, None, None)
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Http`
+    /// * `EventType`=`Http3EventType::StreamTypeSet`
+    /// * `EventData`=`H3StreamTypeSet`.
+    pub fn h3_stream_type_set(
+        stream_id: String, owner: Option<H3Owner>, old: Option<H3StreamType>,
+        new: H3StreamType,
+    ) -> Self {
+        Event {
+            category: EventCategory::Http,
+            ty: EventType::Http3EventType(Http3EventType::StreamTypeSet),
+            data: EventData::H3StreamTypeSet {
+                stream_id,
+                owner,
+                old,
+                new,
+            },
+        }
+    }
+
+    pub fn h3_stream_type_set_min(stream_id: String, new: H3StreamType) -> Self {
+        Event::h3_stream_type_set(stream_id, None, None, new)
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Http`
+    /// * `EventType`=`Http3EventType::FrameCreated`
+    /// * `EventData`=`H3FrameCreated`.
+    pub fn h3_frame_created(
+        stream_id: String, frame: Http3Frame, byte_length: Option<String>,
+        raw: Option<String>,
+    ) -> Self {
+        Event {
+            category: EventCategory::Http,
+            ty: EventType::Http3EventType(Http3EventType::FrameCreated),
+            data: EventData::H3FrameCreated {
+                stream_id,
+                frame,
+                byte_length,
+                raw,
+            },
+        }
+    }
+
+    pub fn h3_frame_created_min(stream_id: String, frame: Http3Frame) -> Self {
+        Event::h3_frame_created(stream_id, frame, None, None)
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Http`
+    /// * `EventType`=`Http3EventType::FrameParsed`
+    /// * `EventData`=`H3FrameParsed`.
+    pub fn h3_frame_parsed(
+        stream_id: String, frame: Http3Frame, byte_length: Option<String>,
+        raw: Option<String>,
+    ) -> Self {
+        Event {
+            category: EventCategory::Http,
+            ty: EventType::Http3EventType(Http3EventType::FrameParsed),
+            data: EventData::H3FrameParsed {
+                stream_id,
+                frame,
+                byte_length,
+                raw,
+            },
+        }
+    }
+
+    pub fn h3_frame_parsed_min(stream_id: String, frame: Http3Frame) -> Self {
+        Event::h3_frame_parsed(stream_id, frame, None, None)
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Http`
+    /// * `EventType`=`Http3EventType::DataMoved`
+    /// * `EventData`=`H3DataMoved`.
+    pub fn h3_data_moved(
+        stream_id: String, offset: Option<String>, length: Option<u64>,
+        from: Option<H3DataRecipient>, to: Option<H3DataRecipient>,
+        raw: Option<String>,
+    ) -> Self {
+        Event {
+            category: EventCategory::Http,
+            ty: EventType::Http3EventType(Http3EventType::DataMoved),
+            data: EventData::H3DataMoved {
+                stream_id,
+                offset,
+                length,
+                from,
+                to,
+                raw,
+            },
+        }
+    }
+
+    pub fn h3_data_moved_min(stream_id: String) -> Self {
+        Event::h3_data_moved(stream_id, None, None, None, None, None)
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Http`
+    /// * `EventType`=`Http3EventType::PushResolved`
+    /// * `EventData`=`H3PushResolved`.
+    pub fn h3_push_resolved(
+        push_id: Option<String>, stream_id: Option<String>,
+        decision: Option<H3PushDecision>,
+    ) -> Self {
+        Event {
+            category: EventCategory::Http,
+            ty: EventType::Http3EventType(Http3EventType::PushResolved),
+            data: EventData::H3PushResolved {
+                push_id,
+                stream_id,
+                decision,
+            },
+        }
+    }
+
+    pub fn h3_push_resolved_min() -> Self {
+        Event::h3_push_resolved(None, None, None)
+    }
+
+    // QPACK events.
+
+    /// Returns:
+    /// * `EventCategory`=`Qpack`
+    /// * `EventType`=`QpackEventType::StateUpdated`
+    /// * `EventData`=`QpackStateUpdated`.
+    pub fn qpack_state_updated(
+        owner: Option<QpackOwner>, dynamic_table_capacity: Option<u64>,
+        dynamic_table_size: Option<u64>, known_received_count: Option<u64>,
+        current_insert_count: Option<u64>,
+    ) -> Self {
+        Event {
+            category: EventCategory::Qpack,
+            ty: EventType::QpackEventType(QpackEventType::StateUpdated),
+            data: EventData::QpackStateUpdated {
+                owner,
+                dynamic_table_capacity,
+                dynamic_table_size,
+                known_received_count,
+                current_insert_count,
+            },
+        }
+    }
+
+    pub fn qpack_state_updated_min() -> Self {
+        Event::qpack_state_updated(None, None, None, None, None)
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Qpack`
+    /// * `EventType`=`QpackEventType::StreamStateUpdated`
+    /// * `EventData`=`QpackStreamStateUpdated`.
+    pub fn qpack_stream_state_updated(
+        stream_id: String, state: QpackStreamState,
+    ) -> Self {
+        Event {
+            category: EventCategory::Qpack,
+            ty: EventType::QpackEventType(QpackEventType::StreamStateUpdated),
+            data: EventData::QpackStreamStateUpdated { stream_id, state },
+        }
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Qpack`
+    /// * `EventType`=`QpackEventType::DynamicTableUpdated`
+    /// * `EventData`=`QpackDynamicTableUpdated`.
+    pub fn qpack_dynamic_table_updated(
+        update_type: QpackUpdateType, entries: Vec<QpackDynamicTableEntry>,
+    ) -> Self {
+        Event {
+            category: EventCategory::Qpack,
+            ty: EventType::QpackEventType(QpackEventType::DynamicTableUpdated),
+            data: EventData::QpackDynamicTableUpdated {
+                update_type,
+                entries,
+            },
+        }
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Qpack`
+    /// * `EventType`=`QpackEventType::HeadersEncoded`
+    /// * `EventData`=`QpackHeadersEncoded`.
+    pub fn qpack_headers_encoded(
+        stream_id: Option<String>, headers: Option<HttpHeader>,
+        block_prefix: QpackHeaderBlockPrefix,
+        header_block: Vec<QpackHeaderBlockRepresentation>, raw: Option<String>,
+    ) -> Self {
+        Event {
+            category: EventCategory::Qpack,
+            ty: EventType::QpackEventType(QpackEventType::HeadersEncoded),
+            data: EventData::QpackHeadersEncoded {
+                stream_id,
+                headers,
+                block_prefix,
+                header_block,
+                raw,
+            },
+        }
+    }
+
+    pub fn qpack_headers_encoded_min(
+        block_prefix: QpackHeaderBlockPrefix,
+        header_block: Vec<QpackHeaderBlockRepresentation>,
+    ) -> Self {
+        Event::qpack_headers_encoded(None, None, block_prefix, header_block, None)
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Qpack`
+    /// * `EventType`=`QpackEventType::HeadersDecoded`
+    /// * `EventData`=`QpackHeadersDecoded`.
+    pub fn qpack_headers_decoded(
+        stream_id: Option<String>, headers: Option<HttpHeader>,
+        block_prefix: QpackHeaderBlockPrefix,
+        header_block: Vec<QpackHeaderBlockRepresentation>, raw: Option<String>,
+    ) -> Self {
+        Event {
+            category: EventCategory::Qpack,
+            ty: EventType::QpackEventType(QpackEventType::HeadersDecoded),
+            data: EventData::QpackHeadersDecoded {
+                stream_id,
+                headers,
+                block_prefix,
+                header_block,
+                raw,
+            },
+        }
+    }
+
+    pub fn qpack_headers_decoded_min(
+        block_prefix: QpackHeaderBlockPrefix,
+        header_block: Vec<QpackHeaderBlockRepresentation>,
+    ) -> Self {
+        Event::qpack_headers_decoded(None, None, block_prefix, header_block, None)
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Qpack`
+    /// * `EventType`=`QpackEventType::InstructionSent`
+    /// * `EventData`=`QpackInstructionSent`.
+    pub fn qpack_instruction_sent(
+        instruction: QPackInstruction, byte_length: Option<String>,
+        raw: Option<String>,
+    ) -> Self {
+        Event {
+            category: EventCategory::Qpack,
+            ty: EventType::QpackEventType(QpackEventType::InstructionSent),
+            data: EventData::QpackInstructionSent {
+                instruction,
+                byte_length,
+                raw,
+            },
+        }
+    }
+
+    pub fn qpack_instruction_sent_min(instruction: QPackInstruction) -> Self {
+        Event::qpack_instruction_sent(instruction, None, None)
+    }
+
+    /// Returns:
+    /// * `EventCategory`=`Qpack`
+    /// * `EventType`=`QpackEventType::InstructionReceived`
+    /// * `EventData`=`QpackInstructionReceived`.
+    pub fn qpack_instruction_received(
+        instruction: QPackInstruction, byte_length: Option<String>,
+        raw: Option<String>,
+    ) -> Self {
+        Event {
+            category: EventCategory::Qpack,
+            ty: EventType::QpackEventType(QpackEventType::InstructionReceived),
+            data: EventData::QpackInstructionReceived {
+                instruction,
+                byte_length,
+                raw,
+            },
+        }
+    }
+
+    pub fn qpack_instruction_received_min(instruction: QPackInstruction) -> Self {
+        Event::qpack_instruction_received(instruction, None, None)
+    }
+
+    /// Checks if the the combination of `EventCategory`, `EventType` and
+    /// `EventData` is valid.
+    pub fn is_valid(&self) -> bool {
+        match (&self.category, &self.ty) {
+            (
+                EventCategory::Connectivity,
+                EventType::ConnectivityEventType(_),
+            ) => matches!(&self.data,
+                EventData::ServerListening { .. } |
+                EventData::ConnectionStarted { .. } |
+                EventData::ConnectionIdUpdated { .. } |
+                EventData::SpinBitUpdated { .. } |
+                EventData::ConnectionStateUpdated { .. }),
+
+            (EventCategory::Transport, EventType::TransportEventType(_)) =>
+                matches!(&self.data,
+                    EventData::TransportParametersSet { .. } |
+                    EventData::DatagramsReceived { .. } |
+                    EventData::DatagramsSent { .. } |
+                    EventData::DatagramDropped { .. } |
+                    EventData::PacketReceived { .. } |
+                    EventData::PacketSent { .. } |
+                    EventData::PacketDropped { .. } |
+                    EventData::PacketBuffered { .. } |
+                    EventData::StreamStateUpdated { .. } |
+                    EventData::FramesProcessed { .. }),
+
+            (EventCategory::Security, EventType::SecurityEventType(_)) =>
+                matches!(&self.data,
+                    EventData::KeyUpdated { .. } |
+                    EventData::KeyRetired { .. }),
+
+            (EventCategory::Recovery, EventType::RecoveryEventType(_)) =>
+                matches!(&self.data,
+                    EventData::RecoveryParametersSet { .. } |
+                    EventData::MetricsUpdated { .. } |
+                    EventData::CongestionStateUpdated { .. } |
+                    EventData::LossTimerSet { .. } |
+                    EventData::PacketLost { .. } |
+                    EventData::MarkedForRetransmit { .. }),
+
+            (EventCategory::Http, EventType::Http3EventType(_)) =>
+                matches!(&self.data,
+                    EventData::H3ParametersSet { .. } |
+                    EventData::H3StreamTypeSet { .. } |
+                    EventData::H3FrameCreated { .. } |
+                    EventData::H3FrameParsed { .. } |
+                    EventData::H3DataMoved { .. } |
+                    EventData::H3PushResolved { .. }),
+
+            (EventCategory::Qpack, EventType::QpackEventType(_)) =>
+                matches!(&self.data,
+                    EventData::QpackStateUpdated { .. } |
+                    EventData::QpackStreamStateUpdated { .. } |
+                    EventData::QpackDynamicTableUpdated { .. } |
+                    EventData::QpackHeadersEncoded { .. } |
+                    EventData::QpackHeadersDecoded { .. } |
+                    EventData::QpackInstructionSent { .. } |
+                    EventData::QpackInstructionReceived { .. }),
+
+            // TODO: in qlog-01 there is no sane default category defined for
+            // GenericEventType
+            (_, EventType::GenericEventType(_)) => matches!(&self.data,
+                EventData::ConnectionError { .. } |
+                EventData::ApplicationError { .. } |
+                EventData::InternalError { .. } |
+                EventData::InternalWarning { .. } |
+                EventData::Message { .. } |
+                EventData::Marker { .. }),
+
+            _ => false,
+        }
+    }
+}
diff --git a/third_party/rust/qlog/src/lib.rs b/third_party/rust/qlog/src/lib.rs
new file mode 100644
index 0000000000..d4a3bb45d0
--- /dev/null
+++ b/third_party/rust/qlog/src/lib.rs
@@ -0,0 +1,2970 @@
+// Copyright (C) 2019, Cloudflare, Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright notice,
+//       this list of conditions and the following disclaimer.
+//
+//     * Redistributions in binary form must reproduce the above copyright
+//       notice, this list of conditions and the following disclaimer in the
+//       documentation and/or other materials provided with the distribution.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+// IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+//! The qlog crate is an implementation of the [qlog main schema] and [qlog QUIC
+//! and HTTP/3 events] that attempts to closely follow the format of the qlog
+//! [TypeScript schema]. This is just a data model and no support is provided
+//! for logging IO, applications can decide themselves the most appropriate
+//! method.
+//!
+//! The crate uses Serde for conversion between Rust and JSON.
+//!
+//! [qlog main schema]: https://tools.ietf.org/html/draft-marx-qlog-main-schema
+//! [qlog QUIC and HTTP/3 events]:
+//! https://quiclog.github.io/internet-drafts/draft-marx-qlog-event-definitions-quic-h3
+//! [TypeScript schema]:
+//! https://github.com/quiclog/qlog/blob/master/TypeScript/draft-01/QLog.ts
+//!
+//! Overview
+//! ---------------
+//! qlog is a hierarchical logging format, with a rough structure of:
+//!
+//! * Log
+//!   * Trace(s)
+//!     * Event(s)
+//!
+//! In practice, a single QUIC connection maps to a single Trace file with one
+//! or more Events. Applications can decide whether to combine Traces from
+//! different connections into the same Log.
+//!
+//! ## Traces
+//!
+//! A [`Trace`] contains metadata such as the [`VantagePoint`] of capture and
+//! the [`Configuration`] of the `Trace`.
+//!
+//! A very important part of the `Trace` is the definition of `event_fields`. A
+//! qlog Event is a vector of [`EventField`]; this provides great flexibility to
+//! log events with any number of `EventFields` in any order. The `event_fields`
+//! property describes the format of event logging and it is important that
+//! events comply with that format. Failing to do so it going to cause problems
+//! for qlog analysis tools. For information is available at
+//! https://tools.ietf.org/html/draft-marx-qlog-main-schema-01#section-3.3.4
+//!
+//! In order to make using qlog a bit easier, this crate expects a qlog Event to
+//! consist of the following EventFields in the following order:
+//! [`EventField::RelativeTime`], [`EventField::Category`],
+//! [`EventField::Event`] and [`EventField::Data`]. A set of methods are
+//! provided to assist in creating a Trace and appending events to it in this
+//! format.
+//!
+//! ## Writing out logs
+//! As events occur during the connection, the application appends them to the
+//! trace. The qlog crate supports two modes of writing logs: the buffered mode
+//! stores everything in memory and requires the application to serialize and
+//! write the output, the streaming mode progressively writes serialized JSON
+//! output to a writer designated by the application.
+//!
+//! ### Creating a Trace
+//!
+//! A typical application needs a single qlog [`Trace`] that it appends QUIC
+//! and/or HTTP/3 events to:
+//!
+//! ```
+//! let mut trace = qlog::Trace::new(
+//!     qlog::VantagePoint {
+//!         name: Some("Example client".to_string()),
+//!         ty: qlog::VantagePointType::Client,
+//!         flow: None,
+//!     },
+//!     Some("Example qlog trace".to_string()),
+//!     Some("Example qlog trace description".to_string()),
+//!     Some(qlog::Configuration {
+//!         time_offset: Some("0".to_string()),
+//!         time_units: Some(qlog::TimeUnits::Ms),
+//!         original_uris: None,
+//!     }),
+//!     None,
+//! );
+//! ```
+//!
+//! ## Adding events
+//!
+//! Qlog Events are added to [`qlog::Trace.events`].
+//!
+//! It is recommended to use the provided utility methods to append semantically
+//! valid events to a trace. However, there is nothing preventing you from
+//! creating the events manually.
+//!
+//! The following example demonstrates how to log a QUIC packet
+//! containing a single Crypto frame. It uses the [`QuicFrame::crypto()`],
+//! [`packet_sent_min()`] and [`push_event()`] methods to create and log a
+//! PacketSent event and its EventData.
+//!
+//! ```
+//! # let mut trace = qlog::Trace::new (
+//! #     qlog::VantagePoint {
+//! #         name: Some("Example client".to_string()),
+//! #         ty: qlog::VantagePointType::Client,
+//! #         flow: None,
+//! #     },
+//! #     Some("Example qlog trace".to_string()),
+//! #     Some("Example qlog trace description".to_string()),
+//! #     Some(qlog::Configuration {
+//! #         time_offset: Some("0".to_string()),
+//! #         time_units: Some(qlog::TimeUnits::Ms),
+//! #         original_uris: None,
+//! #     }),
+//! #     None
+//! # );
+//!
+//! let scid = [0x7e, 0x37, 0xe4, 0xdc, 0xc6, 0x68, 0x2d, 0xa8];
+//! let dcid = [0x36, 0xce, 0x10, 0x4e, 0xee, 0x50, 0x10, 0x1c];
+//!
+//! let pkt_hdr = qlog::PacketHeader::new(
+//!     0,
+//!     Some(1251),
+//!     Some(1224),
+//!     Some(0xff00001b),
+//!     Some(b"7e37e4dcc6682da8"),
+//!     Some(&dcid),
+//! );
+//!
+//! let frames =
+//!     vec![qlog::QuicFrame::crypto("0".to_string(), "1000".to_string())];
+//!
+//! let event = qlog::event::Event::packet_sent_min(
+//!     qlog::PacketType::Initial,
+//!     pkt_hdr,
+//!     Some(frames),
+//! );
+//!
+//! trace.push_event(std::time::Duration::new(0, 0), event);
+//! ```
+//!
+//! ### Serializing
+//!
+//! The qlog crate has only been tested with `serde_json`, however
+//! other serializer targets might work.
+//!
+//! For example, serializing the trace created above:
+//!
+//! ```
+//! # let mut trace = qlog::Trace::new (
+//! #     qlog::VantagePoint {
+//! #         name: Some("Example client".to_string()),
+//! #         ty: qlog::VantagePointType::Client,
+//! #         flow: None,
+//! #     },
+//! #     Some("Example qlog trace".to_string()),
+//! #     Some("Example qlog trace description".to_string()),
+//! #     Some(qlog::Configuration {
+//! #         time_offset: Some("0".to_string()),
+//! #         time_units: Some(qlog::TimeUnits::Ms),
+//! #         original_uris: None,
+//! #     }),
+//! #     None
+//! # );
+//! serde_json::to_string_pretty(&trace).unwrap();
+//! ```
+//!
+//! which would generate the following:
+//!
+//! ```ignore
+//! {
+//!   "vantage_point": {
+//!     "name": "Example client",
+//!     "type": "client"
+//!   },
+//!   "title": "Example qlog trace",
+//!   "description": "Example qlog trace description",
+//!   "configuration": {
+//!     "time_units": "ms",
+//!     "time_offset": "0"
+//!   },
+//!   "event_fields": [
+//!     "relative_time",
+//!     "category",
+//!     "event",
+//!     "data"
+//!   ],
+//!   "events": [
+//!     [
+//!       "0",
+//!       "transport",
+//!       "packet_sent",
+//!       {
+//!         "packet_type": "initial",
+//!         "header": {
+//!           "packet_number": "0",
+//!           "packet_size": 1251,
+//!           "payload_length": 1224,
+//!           "version": "ff00001b",
+//!           "scil": "8",
+//!           "dcil": "8",
+//!           "scid": "7e37e4dcc6682da8",
+//!           "dcid": "36ce104eee50101c"
+//!         },
+//!         "frames": [
+//!           {
+//!             "frame_type": "crypto",
+//!             "offset": "0",
+//!             "length": "100",
+//!           }
+//!         ]
+//!       }
+//!     ]
+//!   ]
+//! }
+//! ```
+//!
+//! Streaming Mode
+//! --------------
+//!
+//! Create the trace:
+//!
+//! ```
+//! let mut trace = qlog::Trace::new(
+//!     qlog::VantagePoint {
+//!         name: Some("Example client".to_string()),
+//!         ty: qlog::VantagePointType::Client,
+//!         flow: None,
+//!     },
+//!     Some("Example qlog trace".to_string()),
+//!     Some("Example qlog trace description".to_string()),
+//!     Some(qlog::Configuration {
+//!         time_offset: Some("0".to_string()),
+//!         time_units: Some(qlog::TimeUnits::Ms),
+//!         original_uris: None,
+//!     }),
+//!     None,
+//! );
+//! ```
+//! Create an object with the [`Write`] trait:
+//!
+//! ```
+//! let mut file = std::fs::File::create("foo.qlog").unwrap();
+//! ```
+//!
+//! Create a [`QlogStreamer`] and start serialization to foo.qlog
+//! using [`start_log()`]:
+//!
+//! ```
+//! # let mut trace = qlog::Trace::new(
+//! #    qlog::VantagePoint {
+//! #        name: Some("Example client".to_string()),
+//! #        ty: qlog::VantagePointType::Client,
+//! #        flow: None,
+//! #    },
+//! #    Some("Example qlog trace".to_string()),
+//! #    Some("Example qlog trace description".to_string()),
+//! #    Some(qlog::Configuration {
+//! #        time_offset: Some("0".to_string()),
+//! #        time_units: Some(qlog::TimeUnits::Ms),
+//! #        original_uris: None,
+//! #    }),
+//! #    None,
+//! # );
+//! # let mut file = std::fs::File::create("foo.qlog").unwrap();
+//! let mut streamer = qlog::QlogStreamer::new(
+//!     qlog::QLOG_VERSION.to_string(),
+//!     Some("Example qlog".to_string()),
+//!     Some("Example qlog description".to_string()),
+//!     None,
+//!     std::time::Instant::now(),
+//!     trace,
+//!     Box::new(file),
+//! );
+//!
+//! streamer.start_log().ok();
+//! ```
+//!
+//! ### Adding simple events
+//!
+//! Once logging has started you can stream events. Simple events
+//! can be written in one step using [`add_event()`]:
+//!
+//! ```
+//! # let mut trace = qlog::Trace::new(
+//! #    qlog::VantagePoint {
+//! #        name: Some("Example client".to_string()),
+//! #        ty: qlog::VantagePointType::Client,
+//! #        flow: None,
+//! #    },
+//! #    Some("Example qlog trace".to_string()),
+//! #    Some("Example qlog trace description".to_string()),
+//! #    Some(qlog::Configuration {
+//! #        time_offset: Some("0".to_string()),
+//! #        time_units: Some(qlog::TimeUnits::Ms),
+//! #        original_uris: None,
+//! #    }),
+//! #    None,
+//! # );
+//! # let mut file = std::fs::File::create("foo.qlog").unwrap();
+//! # let mut streamer = qlog::QlogStreamer::new(
+//! #     qlog::QLOG_VERSION.to_string(),
+//! #     Some("Example qlog".to_string()),
+//! #     Some("Example qlog description".to_string()),
+//! #     None,
+//! #     std::time::Instant::now(),
+//! #     trace,
+//! #     Box::new(file),
+//! # );
+//! let event = qlog::event::Event::metrics_updated_min();
+//! streamer.add_event(event).ok();
+//! ```
+//!
+//! ### Adding events with frames
+//! Some events contain optional arrays of QUIC frames. If the
+//! event has `Some(Vec<QuicFrame>)`, even if it is empty, the
+//! streamer enters a frame serializing mode that must be
+//! finalized before other events can be logged.
+//!
+//! In this example, a `PacketSent` event is created with an
+//! empty frame array and frames are written out later:
+//!
+//! ```
+//! # let mut trace = qlog::Trace::new(
+//! #    qlog::VantagePoint {
+//! #        name: Some("Example client".to_string()),
+//! #        ty: qlog::VantagePointType::Client,
+//! #        flow: None,
+//! #    },
+//! #    Some("Example qlog trace".to_string()),
+//! #    Some("Example qlog trace description".to_string()),
+//! #    Some(qlog::Configuration {
+//! #        time_offset: Some("0".to_string()),
+//! #        time_units: Some(qlog::TimeUnits::Ms),
+//! #        original_uris: None,
+//! #    }),
+//! #    None,
+//! # );
+//! # let mut file = std::fs::File::create("foo.qlog").unwrap();
+//! # let mut streamer = qlog::QlogStreamer::new(
+//! #     qlog::QLOG_VERSION.to_string(),
+//! #     Some("Example qlog".to_string()),
+//! #     Some("Example qlog description".to_string()),
+//! #     None,
+//! #     std::time::Instant::now(),
+//! #     trace,
+//! #     Box::new(file),
+//! # );
+//! let qlog_pkt_hdr = qlog::PacketHeader::with_type(
+//!     qlog::PacketType::OneRtt,
+//!     0,
+//!     Some(1251),
+//!     Some(1224),
+//!     Some(0xff00001b),
+//!     Some(b"7e37e4dcc6682da8"),
+//!     Some(b"36ce104eee50101c"),
+//! );
+//!
+//! let event = qlog::event::Event::packet_sent_min(
+//!     qlog::PacketType::OneRtt,
+//!     qlog_pkt_hdr,
+//!     Some(Vec::new()),
+//! );
+//!
+//! streamer.add_event(event).ok();
+//! ```
+//!
+//! In this example, the frames contained in the QUIC packet
+//! are PING and PADDING. Each frame is written using the
+//! [`add_frame()`] method. Frame writing is concluded with
+//! [`finish_frames()`].
+//!
+//! ```
+//! # let mut trace = qlog::Trace::new(
+//! #    qlog::VantagePoint {
+//! #        name: Some("Example client".to_string()),
+//! #        ty: qlog::VantagePointType::Client,
+//! #        flow: None,
+//! #    },
+//! #    Some("Example qlog trace".to_string()),
+//! #    Some("Example qlog trace description".to_string()),
+//! #    Some(qlog::Configuration {
+//! #        time_offset: Some("0".to_string()),
+//! #        time_units: Some(qlog::TimeUnits::Ms),
+//! #        original_uris: None,
+//! #    }),
+//! #    None,
+//! # );
+//! # let mut file = std::fs::File::create("foo.qlog").unwrap();
+//! # let mut streamer = qlog::QlogStreamer::new(
+//! #     qlog::QLOG_VERSION.to_string(),
+//! #     Some("Example qlog".to_string()),
+//! #     Some("Example qlog description".to_string()),
+//! #     None,
+//! #     std::time::Instant::now(),
+//! #     trace,
+//! #     Box::new(file),
+//! # );
+//!
+//! let ping = qlog::QuicFrame::ping();
+//! let padding = qlog::QuicFrame::padding();
+//!
+//! streamer.add_frame(ping, false).ok();
+//! streamer.add_frame(padding, false).ok();
+//!
+//! streamer.finish_frames().ok();
+//! ```
+//!
+//! Once all events have have been written, the log
+//! can be finalized with [`finish_log()`]:
+//!
+//! ```
+//! # let mut trace = qlog::Trace::new(
+//! #    qlog::VantagePoint {
+//! #        name: Some("Example client".to_string()),
+//! #        ty: qlog::VantagePointType::Client,
+//! #        flow: None,
+//! #    },
+//! #    Some("Example qlog trace".to_string()),
+//! #    Some("Example qlog trace description".to_string()),
+//! #    Some(qlog::Configuration {
+//! #        time_offset: Some("0".to_string()),
+//! #        time_units: Some(qlog::TimeUnits::Ms),
+//! #        original_uris: None,
+//! #    }),
+//! #    None,
+//! # );
+//! # let mut file = std::fs::File::create("foo.qlog").unwrap();
+//! # let mut streamer = qlog::QlogStreamer::new(
+//! #     qlog::QLOG_VERSION.to_string(),
+//! #     Some("Example qlog".to_string()),
+//! #     Some("Example qlog description".to_string()),
+//! #     None,
+//! #     std::time::Instant::now(),
+//! #     trace,
+//! #     Box::new(file),
+//! # );
+//! streamer.finish_log().ok();
+//! ```
+//!
+//! ### Serializing
+//!
+//! Serialization to JSON occurs as methods on the [`QlogStreamer`]
+//! are called. No additional steps are required.
+//!
+//! [`Trace`]: struct.Trace.html
+//! [`VantagePoint`]: struct.VantagePoint.html
+//! [`Configuration`]: struct.Configuration.html
+//! [`EventField`]: enum.EventField.html
+//! [`EventField::RelativeTime`]: enum.EventField.html#variant.RelativeTime
+//! [`EventField::Category`]: enum.EventField.html#variant.Category
+//! [`EventField::Type`]: enum.EventField.html#variant.Type
+//! [`EventField::Data`]: enum.EventField.html#variant.Data
+//! [`qlog::Trace.events`]: struct.Trace.html#structfield.events
+//! [`push_event()`]: struct.Trace.html#method.push_event
+//! [`packet_sent_min()`]: event/struct.Event.html#method.packet_sent_min
+//! [`QuicFrame::crypto()`]: enum.QuicFrame.html#variant.Crypto
+//! [`QlogStreamer`]: struct.QlogStreamer.html
+//! [`Write`]: https://doc.rust-lang.org/std/io/trait.Write.html
+//! [`start_log()`]: struct.QlogStreamer.html#method.start_log
+//! [`add_event()`]: struct.QlogStreamer.html#method.add_event
+//! [`add_frame()`]: struct.QlogStreamer.html#method.add_frame
+//! [`finish_frames()`]: struct.QlogStreamer.html#method.finish_frames
+//! [`finish_log()`]: struct.QlogStreamer.html#method.finish_log
+
+use serde::Serialize;
+
+/// A quiche qlog error.
+#[derive(Debug)]
+pub enum Error {
+    /// There is no more work to do.
+    Done,
+
+    /// The operation cannot be completed because it was attempted
+    /// in an invalid state.
+    InvalidState,
+
+    /// I/O error.
+    IoError(std::io::Error),
+}
+
+impl std::fmt::Display for Error {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        write!(f, "{:?}", self)
+    }
+}
+
+impl std::error::Error for Error {
+    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+        None
+    }
+}
+
+impl std::convert::From<std::io::Error> for Error {
+    fn from(err: std::io::Error) -> Self {
+        Error::IoError(err)
+    }
+}
+
+pub const QLOG_VERSION: &str = "draft-02-wip";
+
+/// A specialized [`Result`] type for quiche qlog operations.
+///
+/// This type is used throughout the public API for any operation that
+/// can produce an error.
+///
+/// [`Result`]: https://doc.rust-lang.org/std/result/enum.Result.html
+pub type Result<T> = std::result::Result<T, Error>;
+
+#[serde_with::skip_serializing_none]
+#[derive(Serialize, Clone)]
+pub struct Qlog {
+    pub qlog_version: String,
+    pub title: Option<String>,
+    pub description: Option<String>,
+    pub summary: Option<String>,
+
+    pub traces: Vec<Trace>,
+}
+
+impl Default for Qlog {
+    fn default() -> Self {
+        Qlog {
+            qlog_version: QLOG_VERSION.to_string(),
+            title: Some("Default qlog title".to_string()),
+            description: Some("Default qlog description".to_string()),
+            summary: Some("Default qlog title".to_string()),
+            traces: Vec::new(),
+        }
+    }
+}
+
+#[derive(PartialEq)]
+pub enum StreamerState {
+    Initial,
+    Ready,
+    WritingFrames,
+    Finished,
+}
+
+/// A helper object specialized for streaming JSON-serialized qlog to a
+/// [`Write`] trait.
+///
+/// The object is responsible for the `Qlog` object that contains the provided
+/// `Trace`.
+///
+/// Serialization is progressively driven by method calls; once log streaming is
+/// started, `event::Events` can be written using `add_event()`. Some events
+/// can contain an array of `QuicFrame`s, when writing such an event, the
+/// streamer enters a frame-serialization mode where frames are be progressively
+/// written using `add_frame()`. This mode is concluded using
+/// `finished_frames()`. While serializing frames, any attempts to log
+/// additional events are ignored.
+///
+/// [`Write`]: https://doc.rust-lang.org/std/io/trait.Write.html
+pub struct QlogStreamer {
+    start_time: std::time::Instant,
+    writer: Box<dyn std::io::Write + Send + Sync>,
+    qlog: Qlog,
+    state: StreamerState,
+    first_event: bool,
+    first_frame: bool,
+}
+
+impl QlogStreamer {
+    /// Creates a QlogStreamer object.
+    ///
+    /// It owns a `Qlog` object that contains the provided `Trace`, which must
+    /// have the following ordered-set of names EventFields:
+    ///
+    /// ["relative_time", "category", "event".to_string(), "data"]
+    ///
+    /// All serialization will be written to the provided `Write`.
+    pub fn new(
+        qlog_version: String, title: Option<String>, description: Option<String>,
+        summary: Option<String>, start_time: std::time::Instant, trace: Trace,
+        writer: Box<dyn std::io::Write + Send + Sync>,
+    ) -> Self {
+        let qlog = Qlog {
+            qlog_version,
+            title,
+            description,
+            summary,
+            traces: vec![trace],
+        };
+
+        QlogStreamer {
+            start_time,
+            writer,
+            qlog,
+            state: StreamerState::Initial,
+            first_event: true,
+            first_frame: false,
+        }
+    }
+
+    /// Starts qlog streaming serialization.
+    ///
+    /// This writes out the JSON-serialized form of all information up to qlog
+    /// `Trace`'s array of `EventField`s. EventFields are separately appended
+    /// using functions that accept and `event::Event`.
+    pub fn start_log(&mut self) -> Result<()> {
+        if self.state != StreamerState::Initial {
+            return Err(Error::Done);
+        }
+
+        // A qlog contains a trace holding a vector of events that we want to
+        // serialize in a streaming manner. So at the start of serialization,
+        // take off all closing delimiters, and leave us in a state to accept
+        // new events.
+        match serde_json::to_string(&self.qlog) {
+            Ok(mut out) => {
+                out.truncate(out.len() - 4);
+
+                self.writer.as_mut().write_all(out.as_bytes())?;
+
+                self.state = StreamerState::Ready;
+
+                self.first_event = self.qlog.traces[0].events.is_empty();
+            },
+
+            _ => return Err(Error::Done),
+        }
+
+        Ok(())
+    }
+
+    /// Finishes qlog streaming serialization.
+    ///
+    /// The JSON-serialized output has remaining close delimiters added.
+    /// After this is called, no more serialization will occur.
+    pub fn finish_log(&mut self) -> Result<()> {
+        if self.state == StreamerState::Initial ||
+            self.state == StreamerState::Finished
+        {
+            return Err(Error::InvalidState);
+        }
+
+        self.writer.as_mut().write_all(b"]}]}")?;
+
+        self.state = StreamerState::Finished;
+
+        self.writer.as_mut().flush()?;
+
+        Ok(())
+    }
+
+    /// Writes a JSON-serialized `EventField`s.
+    ///
+    /// Some qlog events can contain `QuicFrames`. If this is detected `true` is
+    /// returned and the streamer enters a frame-serialization mode that is only
+    /// concluded by `finish_frames()`. In this mode, attempts to log additional
+    /// events are ignored.
+    ///
+    /// If the event contains no array of `QuicFrames` return `false`.
+    pub fn add_event(&mut self, event: event::Event) -> Result<bool> {
+        if self.state != StreamerState::Ready {
+            return Err(Error::InvalidState);
+        }
+
+        let event_time = if cfg!(test) {
+            std::time::Duration::from_secs(0)
+        } else {
+            self.start_time.elapsed()
+        };
+
+        let rel = match &self.qlog.traces[0].configuration {
+            Some(conf) => match conf.time_units {
+                Some(TimeUnits::Ms) => event_time.as_millis().to_string(),
+
+                Some(TimeUnits::Us) => event_time.as_micros().to_string(),
+
+                None => String::from(""),
+            },
+
+            None => String::from(""),
+        };
+
+        let (ev_data, contains_frames) = match serde_json::to_string(&event.data)
+        {
+            Ok(mut ev_data_out) =>
+                if let Some(f) = event.data.contains_quic_frames() {
+                    ev_data_out.truncate(ev_data_out.len() - 2);
+
+                    if f == 0 {
+                        self.first_frame = true;
+                    }
+
+                    (ev_data_out, true)
+                } else {
+                    (ev_data_out, false)
+                },
+
+            _ => return Err(Error::Done),
+        };
+
+        let maybe_comma = if self.first_event {
+            self.first_event = false;
+            ""
+        } else {
+            ","
+        };
+
+        let maybe_terminate = if contains_frames { "" } else { "]" };
+
+        let ev_time = serde_json::to_string(&EventField::RelativeTime(rel)).ok();
+        let ev_cat =
+            serde_json::to_string(&EventField::Category(event.category)).ok();
+        let ev_ty = serde_json::to_string(&EventField::Event(event.ty)).ok();
+
+        if let (Some(ev_time), Some(ev_cat), Some(ev_ty)) =
+            (ev_time, ev_cat, ev_ty)
+        {
+            let out = format!(
+                "{}[{},{},{},{}{}",
+                maybe_comma, ev_time, ev_cat, ev_ty, ev_data, maybe_terminate
+            );
+
+            self.writer.as_mut().write_all(out.as_bytes())?;
+
+            if contains_frames {
+                self.state = StreamerState::WritingFrames
+            } else {
+                self.state = StreamerState::Ready
+            };
+
+            return Ok(contains_frames);
+        }
+
+        Err(Error::Done)
+    }
+
+    /// Writes a JSON-serialized `QuicFrame`.
+    ///
+    /// Only valid while in the frame-serialization mode.
+    pub fn add_frame(&mut self, frame: QuicFrame, last: bool) -> Result<()> {
+        if self.state != StreamerState::WritingFrames {
+            return Err(Error::InvalidState);
+        }
+
+        match serde_json::to_string(&frame) {
+            Ok(mut out) => {
+                if !self.first_frame {
+                    out.insert(0, ',');
+                } else {
+                    self.first_frame = false;
+                }
+
+                self.writer.as_mut().write_all(out.as_bytes())?;
+
+                if last {
+                    self.finish_frames()?;
+                }
+            },
+
+            _ => return Err(Error::Done),
+        }
+
+        Ok(())
+    }
+
+    /// Concludes `QuicFrame` streaming serialization.
+    ///
+    /// Only valid while in the frame-serialization mode.
+    pub fn finish_frames(&mut self) -> Result<()> {
+        if self.state != StreamerState::WritingFrames {
+            return Err(Error::InvalidState);
+        }
+
+        self.writer.as_mut().write_all(b"]}]")?;
+        self.state = StreamerState::Ready;
+
+        Ok(())
+    }
+
+    /// Returns the writer.
+    #[allow(clippy::borrowed_box)]
+    pub fn writer(&self) -> &Box<dyn std::io::Write + Send + Sync> {
+        &self.writer
+    }
+}
+
+#[serde_with::skip_serializing_none]
+#[derive(Serialize, Clone)]
+pub struct Trace {
+    pub vantage_point: VantagePoint,
+    pub title: Option<String>,
+    pub description: Option<String>,
+
+    pub configuration: Option<Configuration>,
+
+    pub common_fields: Option<CommonFields>,
+    pub event_fields: Vec<String>,
+
+    pub events: Vec<Vec<EventField>>,
+}
+
+/// Helper functions for using a qlog trace.
+impl Trace {
+    /// Creates a new qlog trace with the hard-coded event_fields
+    /// ["relative_time", "category", "event", "data"]
+    pub fn new(
+        vantage_point: VantagePoint, title: Option<String>,
+        description: Option<String>, configuration: Option<Configuration>,
+        common_fields: Option<CommonFields>,
+    ) -> Self {
+        Trace {
+            vantage_point,
+            title,
+            description,
+            configuration,
+            common_fields,
+            event_fields: vec![
+                "relative_time".to_string(),
+                "category".to_string(),
+                "event".to_string(),
+                "data".to_string(),
+            ],
+            events: Vec::new(),
+        }
+    }
+
+    pub fn push_event(
+        &mut self, relative_time: std::time::Duration, event: crate::event::Event,
+    ) {
+        let rel = match &self.configuration {
+            Some(conf) => match conf.time_units {
+                Some(TimeUnits::Ms) => relative_time.as_millis().to_string(),
+
+                Some(TimeUnits::Us) => relative_time.as_micros().to_string(),
+
+                None => String::from(""),
+            },
+
+            None => String::from(""),
+        };
+
+        self.events.push(vec![
+            EventField::RelativeTime(rel),
+            EventField::Category(event.category),
+            EventField::Event(event.ty),
+            EventField::Data(event.data),
+        ]);
+    }
+}
+
+#[serde_with::skip_serializing_none]
+#[derive(Serialize, Clone)]
+pub struct VantagePoint {
+    pub name: Option<String>,
+
+    #[serde(rename = "type")]
+    pub ty: VantagePointType,
+
+    pub flow: Option<VantagePointType>,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum VantagePointType {
+    Client,
+    Server,
+    Network,
+    Unknown,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum TimeUnits {
+    Ms,
+    Us,
+}
+
+#[serde_with::skip_serializing_none]
+#[derive(Serialize, Clone)]
+pub struct Configuration {
+    pub time_units: Option<TimeUnits>,
+    pub time_offset: Option<String>,
+
+    pub original_uris: Option<Vec<String>>,
+    /* TODO
+     * additionalUserSpecifiedProperty */
+}
+
+impl Default for Configuration {
+    fn default() -> Self {
+        Configuration {
+            time_units: Some(TimeUnits::Ms),
+            time_offset: Some("0".to_string()),
+            original_uris: None,
+        }
+    }
+}
+
+#[serde_with::skip_serializing_none]
+#[derive(Serialize, Clone, Default)]
+pub struct CommonFields {
+    pub group_id: Option<String>,
+    pub protocol_type: Option<String>,
+
+    pub reference_time: Option<String>,
+    /* TODO
+     * additionalUserSpecifiedProperty */
+}
+
+#[derive(Serialize, Clone)]
+#[serde(untagged)]
+pub enum EventType {
+    ConnectivityEventType(ConnectivityEventType),
+
+    TransportEventType(TransportEventType),
+
+    SecurityEventType(SecurityEventType),
+
+    RecoveryEventType(RecoveryEventType),
+
+    Http3EventType(Http3EventType),
+
+    QpackEventType(QpackEventType),
+
+    GenericEventType(GenericEventType),
+}
+
+#[derive(Serialize, Clone)]
+#[serde(untagged)]
+#[allow(clippy::large_enum_variant)]
+pub enum EventField {
+    RelativeTime(String),
+
+    Category(EventCategory),
+
+    Event(EventType),
+
+    Data(EventData),
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum EventCategory {
+    Connectivity,
+    Security,
+    Transport,
+    Recovery,
+    Http,
+    Qpack,
+
+    Error,
+    Warning,
+    Info,
+    Debug,
+    Verbose,
+    Simulation,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum ConnectivityEventType {
+    ServerListening,
+    ConnectionStarted,
+    ConnectionIdUpdated,
+    SpinBitUpdated,
+    ConnectionStateUpdated,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum TransportEventType {
+    ParametersSet,
+
+    DatagramsSent,
+    DatagramsReceived,
+    DatagramDropped,
+
+    PacketSent,
+    PacketReceived,
+    PacketDropped,
+    PacketBuffered,
+
+    FramesProcessed,
+
+    StreamStateUpdated,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum TransportEventTrigger {
+    Line,
+    Retransmit,
+    KeysUnavailable,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum SecurityEventType {
+    KeyUpdated,
+    KeyRetired,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum SecurityEventTrigger {
+    Tls,
+    Implicit,
+    RemoteUpdate,
+    LocalUpdate,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum RecoveryEventType {
+    ParametersSet,
+    MetricsUpdated,
+    CongestionStateUpdated,
+    LossTimerSet,
+    LossTimerTriggered,
+    PacketLost,
+    MarkedForRetransmit,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum RecoveryEventTrigger {
+    AckReceived,
+    PacketSent,
+    Alarm,
+    Unknown,
+}
+
+// ================================================================== //
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum KeyType {
+    ServerInitialSecret,
+    ClientInitialSecret,
+
+    ServerHandshakeSecret,
+    ClientHandshakeSecret,
+
+    Server0RttSecret,
+    Client0RttSecret,
+
+    Server1RttSecret,
+    Client1RttSecret,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum ConnectionState {
+    Attempted,
+    Reset,
+    Handshake,
+    Active,
+    Keepalive,
+    Draining,
+    Closed,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum TransportOwner {
+    Local,
+    Remote,
+}
+
+#[derive(Serialize, Clone)]
+pub struct PreferredAddress {
+    pub ip_v4: String,
+    pub ip_v6: String,
+
+    pub port_v4: u64,
+    pub port_v6: u64,
+
+    pub connection_id: String,
+    pub stateless_reset_token: String,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum StreamSide {
+    Sending,
+    Receiving,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum StreamState {
+    // bidirectional stream states, draft-23 3.4.
+    Idle,
+    Open,
+    HalfClosedLocal,
+    HalfClosedRemote,
+    Closed,
+
+    // sending-side stream states, draft-23 3.1.
+    Ready,
+    Send,
+    DataSent,
+    ResetSent,
+    ResetReceived,
+
+    // receive-side stream states, draft-23 3.2.
+    Receive,
+    SizeKnown,
+    DataRead,
+    ResetRead,
+
+    // both-side states
+    DataReceived,
+
+    // qlog-defined
+    Destroyed,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum TimerType {
+    Ack,
+    Pto,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum H3Owner {
+    Local,
+    Remote,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum H3StreamType {
+    Data,
+    Control,
+    Push,
+    Reserved,
+    QpackEncode,
+    QpackDecode,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum H3DataRecipient {
+    Application,
+    Transport,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum H3PushDecision {
+    Claimed,
+    Abandoned,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum QpackOwner {
+    Local,
+    Remote,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum QpackStreamState {
+    Blocked,
+    Unblocked,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum QpackUpdateType {
+    Added,
+    Evicted,
+}
+
+#[derive(Serialize, Clone)]
+pub struct QpackDynamicTableEntry {
+    pub index: u64,
+    pub name: Option<String>,
+    pub value: Option<String>,
+}
+
+#[derive(Serialize, Clone)]
+pub struct QpackHeaderBlockPrefix {
+    pub required_insert_count: u64,
+    pub sign_bit: bool,
+    pub delta_base: u64,
+}
+
+#[serde_with::skip_serializing_none]
+#[derive(Serialize, Clone)]
+#[serde(untagged)]
+#[allow(clippy::large_enum_variant)]
+pub enum EventData {
+    // ================================================================== //
+    // CONNECTIVITY
+    ServerListening {
+        ip_v4: Option<String>,
+        ip_v6: Option<String>,
+        port_v4: u64,
+        port_v6: u64,
+
+        quic_versions: Option<Vec<String>>,
+        alpn_values: Option<Vec<String>>,
+
+        stateless_reset_required: Option<bool>,
+    },
+
+    ConnectionStarted {
+        ip_version: String,
+        src_ip: String,
+        dst_ip: String,
+
+        protocol: Option<String>,
+        src_port: u64,
+        dst_port: u64,
+
+        quic_version: Option<String>,
+        src_cid: Option<String>,
+        dst_cid: Option<String>,
+    },
+
+    ConnectionIdUpdated {
+        src_old: Option<String>,
+        src_new: Option<String>,
+
+        dst_old: Option<String>,
+        dst_new: Option<String>,
+    },
+
+    SpinBitUpdated {
+        state: bool,
+    },
+
+    ConnectionStateUpdated {
+        old: Option<ConnectionState>,
+        new: ConnectionState,
+    },
+
+    // ================================================================== //
+    // SECURITY
+    KeyUpdated {
+        key_type: KeyType,
+        old: Option<String>,
+        new: String,
+        generation: Option<u64>,
+    },
+
+    KeyRetired {
+        key_type: KeyType,
+        key: Option<String>,
+        generation: Option<u64>,
+    },
+
+    // ================================================================== //
+    // TRANSPORT
+    TransportParametersSet {
+        owner: Option<TransportOwner>,
+
+        resumption_allowed: Option<bool>,
+        early_data_enabled: Option<bool>,
+        alpn: Option<String>,
+        version: Option<String>,
+        tls_cipher: Option<String>,
+
+        original_connection_id: Option<String>,
+        stateless_reset_token: Option<String>,
+        disable_active_migration: Option<bool>,
+
+        idle_timeout: Option<u64>,
+        max_packet_size: Option<u64>,
+        ack_delay_exponent: Option<u64>,
+        max_ack_delay: Option<u64>,
+        active_connection_id_limit: Option<u64>,
+
+        initial_max_data: Option<String>,
+        initial_max_stream_data_bidi_local: Option<String>,
+        initial_max_stream_data_bidi_remote: Option<String>,
+        initial_max_stream_data_uni: Option<String>,
+        initial_max_streams_bidi: Option<String>,
+        initial_max_streams_uni: Option<String>,
+
+        preferred_address: Option<PreferredAddress>,
+    },
+
+    DatagramsReceived {
+        count: Option<u64>,
+        byte_length: Option<u64>,
+    },
+
+    DatagramsSent {
+        count: Option<u64>,
+        byte_length: Option<u64>,
+    },
+
+    DatagramDropped {
+        byte_length: Option<u64>,
+    },
+
+    PacketReceived {
+        packet_type: PacketType,
+        header: PacketHeader,
+        // `frames` is defined here in the QLog schema specification. However,
+        // our streaming serializer requires serde to put the object at the end,
+        // so we define it there and depend on serde's preserve_order feature.
+        is_coalesced: Option<bool>,
+
+        raw_encrypted: Option<String>,
+        raw_decrypted: Option<String>,
+        frames: Option<Vec<QuicFrame>>,
+    },
+
+    PacketSent {
+        packet_type: PacketType,
+        header: PacketHeader,
+        // `frames` is defined here in the QLog schema specification. However,
+        // our streaming serializer requires serde to put the object at the end,
+        // so we define it there and depend on serde's preserve_order feature.
+        is_coalesced: Option<bool>,
+
+        raw_encrypted: Option<String>,
+        raw_decrypted: Option<String>,
+        frames: Option<Vec<QuicFrame>>,
+    },
+
+    PacketDropped {
+        packet_type: Option<PacketType>,
+        packet_size: Option<u64>,
+
+        raw: Option<String>,
+    },
+
+    PacketBuffered {
+        packet_type: PacketType,
+        packet_number: String,
+    },
+
+    StreamStateUpdated {
+        stream_id: String,
+        stream_type: Option<StreamType>,
+
+        old: Option<StreamState>,
+        new: StreamState,
+
+        stream_side: Option<StreamSide>,
+    },
+
+    FramesProcessed {
+        frames: Vec<QuicFrame>,
+    },
+
+    // ================================================================== //
+    // RECOVERY
+    RecoveryParametersSet {
+        reordering_threshold: Option<u64>,
+        time_threshold: Option<u64>,
+        timer_granularity: Option<u64>,
+        initial_rtt: Option<u64>,
+
+        max_datagram_size: Option<u64>,
+        initial_congestion_window: Option<u64>,
+        minimum_congestion_window: Option<u64>,
+        loss_reduction_factor: Option<u64>,
+        persistent_congestion_threshold: Option<u64>,
+    },
+
+    MetricsUpdated {
+        min_rtt: Option<u64>,
+        smoothed_rtt: Option<u64>,
+        latest_rtt: Option<u64>,
+        rtt_variance: Option<u64>,
+
+        max_ack_delay: Option<u64>,
+        pto_count: Option<u64>,
+
+        congestion_window: Option<u64>,
+        bytes_in_flight: Option<u64>,
+
+        ssthresh: Option<u64>,
+
+        // qlog defined
+        packets_in_flight: Option<u64>,
+        in_recovery: Option<bool>,
+
+        pacing_rate: Option<u64>,
+    },
+
+    CongestionStateUpdated {
+        old: Option<String>,
+        new: String,
+    },
+
+    LossTimerSet {
+        timer_type: Option<TimerType>,
+        timeout: Option<String>,
+    },
+
+    PacketLost {
+        packet_type: PacketType,
+        packet_number: String,
+
+        header: Option<PacketHeader>,
+        frames: Vec<QuicFrame>,
+    },
+
+    MarkedForRetransmit {
+        frames: Vec<QuicFrame>,
+    },
+
+    // ================================================================== //
+    // HTTP/3
+    H3ParametersSet {
+        owner: Option<H3Owner>,
+
+        max_header_list_size: Option<u64>,
+        max_table_capacity: Option<u64>,
+        blocked_streams_count: Option<u64>,
+
+        push_allowed: Option<bool>,
+
+        waits_for_settings: Option<bool>,
+    },
+
+    H3StreamTypeSet {
+        stream_id: String,
+        owner: Option<H3Owner>,
+
+        old: Option<H3StreamType>,
+        new: H3StreamType,
+    },
+
+    H3FrameCreated {
+        stream_id: String,
+        frame: Http3Frame,
+        byte_length: Option<String>,
+
+        raw: Option<String>,
+    },
+
+    H3FrameParsed {
+        stream_id: String,
+        frame: Http3Frame,
+        byte_length: Option<String>,
+
+        raw: Option<String>,
+    },
+
+    H3DataMoved {
+        stream_id: String,
+        offset: Option<String>,
+        length: Option<u64>,
+
+        from: Option<H3DataRecipient>,
+        to: Option<H3DataRecipient>,
+
+        raw: Option<String>,
+    },
+
+    H3PushResolved {
+        push_id: Option<String>,
+        stream_id: Option<String>,
+
+        decision: Option<H3PushDecision>,
+    },
+
+    // ================================================================== //
+    // QPACK
+    QpackStateUpdated {
+        owner: Option<QpackOwner>,
+
+        dynamic_table_capacity: Option<u64>,
+        dynamic_table_size: Option<u64>,
+
+        known_received_count: Option<u64>,
+        current_insert_count: Option<u64>,
+    },
+
+    QpackStreamStateUpdated {
+        stream_id: String,
+
+        state: QpackStreamState,
+    },
+
+    QpackDynamicTableUpdated {
+        update_type: QpackUpdateType,
+
+        entries: Vec<QpackDynamicTableEntry>,
+    },
+
+    QpackHeadersEncoded {
+        stream_id: Option<String>,
+
+        headers: Option<HttpHeader>,
+
+        block_prefix: QpackHeaderBlockPrefix,
+        header_block: Vec<QpackHeaderBlockRepresentation>,
+
+        raw: Option<String>,
+    },
+
+    QpackHeadersDecoded {
+        stream_id: Option<String>,
+
+        headers: Option<HttpHeader>,
+
+        block_prefix: QpackHeaderBlockPrefix,
+        header_block: Vec<QpackHeaderBlockRepresentation>,
+
+        raw: Option<String>,
+    },
+
+    QpackInstructionSent {
+        instruction: QPackInstruction,
+        byte_length: Option<String>,
+
+        raw: Option<String>,
+    },
+
+    QpackInstructionReceived {
+        instruction: QPackInstruction,
+        byte_length: Option<String>,
+
+        raw: Option<String>,
+    },
+
+    // ================================================================== //
+    // Generic
+    ConnectionError {
+        code: Option<ConnectionErrorCode>,
+        description: Option<String>,
+    },
+
+    ApplicationError {
+        code: Option<ApplicationErrorCode>,
+        description: Option<String>,
+    },
+
+    InternalError {
+        code: Option<u64>,
+        description: Option<String>,
+    },
+
+    InternalWarning {
+        code: Option<u64>,
+        description: Option<String>,
+    },
+
+    Message {
+        message: String,
+    },
+
+    Marker {
+        marker_type: String,
+        message: Option<String>,
+    },
+}
+
+impl EventData {
+    /// Returns size of `EventData` array of `QuicFrame`s if it exists.
+    pub fn contains_quic_frames(&self) -> Option<usize> {
+        // For some EventData variants, the frame array is optional
+        // but for others it is mandatory.
+        match self {
+            EventData::PacketSent { frames, .. } |
+            EventData::PacketReceived { frames, .. } =>
+                if let Some(f) = frames {
+                    Some(f.len())
+                } else {
+                    None
+                },
+
+            EventData::PacketLost { frames, .. } |
+            EventData::MarkedForRetransmit { frames } |
+            EventData::FramesProcessed { frames } => Some(frames.len()),
+
+            _ => None,
+        }
+    }
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum PacketType {
+    Initial,
+    Handshake,
+
+    #[serde(rename = "0RTT")]
+    ZeroRtt,
+
+    #[serde(rename = "1RTT")]
+    OneRtt,
+
+    Retry,
+    VersionNegotiation,
+    Unknown,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum Http3EventType {
+    ParametersSet,
+    StreamTypeSet,
+    FrameCreated,
+    FrameParsed,
+    DataMoved,
+    PushResolved,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum QpackEventType {
+    StateUpdated,
+    StreamStateUpdated,
+    DynamicTableUpdated,
+    HeadersEncoded,
+    HeadersDecoded,
+    InstructionSent,
+    InstructionReceived,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum QuicFrameTypeName {
+    Padding,
+    Ping,
+    Ack,
+    ResetStream,
+    StopSending,
+    Crypto,
+    NewToken,
+    Stream,
+    MaxData,
+    MaxStreamData,
+    MaxStreams,
+    DataBlocked,
+    StreamDataBlocked,
+    StreamsBlocked,
+    NewConnectionId,
+    RetireConnectionId,
+    PathChallenge,
+    PathResponse,
+    ConnectionClose,
+    ApplicationClose,
+    HandshakeDone,
+    Datagram,
+    Unknown,
+}
+
+// TODO: search for pub enum Error { to see how best to encode errors in qlog.
+#[serde_with::skip_serializing_none]
+#[derive(Clone, Serialize)]
+pub struct PacketHeader {
+    pub packet_number: String,
+    pub packet_size: Option<u64>,
+    pub payload_length: Option<u64>,
+    pub version: Option<String>,
+    pub scil: Option<String>,
+    pub dcil: Option<String>,
+    pub scid: Option<String>,
+    pub dcid: Option<String>,
+}
+
+impl PacketHeader {
+    /// Creates a new PacketHeader.
+    pub fn new(
+        packet_number: u64, packet_size: Option<u64>,
+        payload_length: Option<u64>, version: Option<u32>, scid: Option<&[u8]>,
+        dcid: Option<&[u8]>,
+    ) -> Self {
+        let (scil, scid) = match scid {
+            Some(cid) => (
+                Some(cid.len().to_string()),
+                Some(format!("{}", HexSlice::new(&cid))),
+            ),
+
+            None => (None, None),
+        };
+
+        let (dcil, dcid) = match dcid {
+            Some(cid) => (
+                Some(cid.len().to_string()),
+                Some(format!("{}", HexSlice::new(&cid))),
+            ),
+
+            None => (None, None),
+        };
+
+        let version = match version {
+            Some(v) => Some(format!("{:x?}", v)),
+
+            None => None,
+        };
+
+        PacketHeader {
+            packet_number: packet_number.to_string(),
+            packet_size,
+            payload_length,
+            version,
+            scil,
+            dcil,
+            scid,
+            dcid,
+        }
+    }
+
+    /// Creates a new PacketHeader.
+    ///
+    /// Once a QUIC connection has formed, version, dcid and scid are stable, so
+    /// there are space benefits to not logging them in every packet, especially
+    /// PacketType::OneRtt.
+    pub fn with_type(
+        ty: PacketType, packet_number: u64, packet_size: Option<u64>,
+        payload_length: Option<u64>, version: Option<u32>, scid: Option<&[u8]>,
+        dcid: Option<&[u8]>,
+    ) -> Self {
+        match ty {
+            PacketType::OneRtt => PacketHeader::new(
+                packet_number,
+                packet_size,
+                payload_length,
+                None,
+                None,
+                None,
+            ),
+
+            _ => PacketHeader::new(
+                packet_number,
+                packet_size,
+                payload_length,
+                version,
+                scid,
+                dcid,
+            ),
+        }
+    }
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum StreamType {
+    Bidirectional,
+    Unidirectional,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum ErrorSpace {
+    TransportError,
+    ApplicationError,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum GenericEventType {
+    ConnectionError,
+    ApplicationError,
+    InternalError,
+    InternalWarning,
+
+    Message,
+    Marker,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(untagged)]
+pub enum ConnectionErrorCode {
+    TransportError(TransportError),
+    CryptoError(CryptoError),
+    Value(u64),
+}
+
+#[derive(Serialize, Clone)]
+#[serde(untagged)]
+pub enum ApplicationErrorCode {
+    ApplicationError(ApplicationError),
+    Value(u64),
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum TransportError {
+    NoError,
+    InternalError,
+    ServerBusy,
+    FlowControlError,
+    StreamLimitError,
+    StreamStateError,
+    FinalSizeError,
+    FrameEncodingError,
+    TransportParameterError,
+    ProtocolViolation,
+    InvalidMigration,
+    CryptoBufferExceeded,
+    Unknown,
+}
+
+// TODO
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum CryptoError {
+    Prefix,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum ApplicationError {
+    HttpNoError,
+    HttpGeneralProtocolError,
+    HttpInternalError,
+    HttpRequestCancelled,
+    HttpIncompleteRequest,
+    HttpConnectError,
+    HttpFrameError,
+    HttpExcessiveLoad,
+    HttpVersionFallback,
+    HttpIdError,
+    HttpStreamCreationError,
+    HttpClosedCriticalStream,
+    HttpEarlyResponse,
+    HttpMissingSettings,
+    HttpUnexpectedFrame,
+    HttpRequestRejection,
+    HttpSettingsError,
+    Unknown,
+}
+
+#[serde_with::skip_serializing_none]
+#[derive(Serialize, Clone)]
+#[serde(untagged)]
+pub enum QuicFrame {
+    Padding {
+        frame_type: QuicFrameTypeName,
+    },
+
+    Ping {
+        frame_type: QuicFrameTypeName,
+    },
+
+    Ack {
+        frame_type: QuicFrameTypeName,
+        ack_delay: Option<String>,
+        acked_ranges: Option<Vec<(u64, u64)>>,
+
+        ect1: Option<String>,
+
+        ect0: Option<String>,
+
+        ce: Option<String>,
+    },
+
+    ResetStream {
+        frame_type: QuicFrameTypeName,
+        stream_id: String,
+        error_code: u64,
+        final_size: String,
+    },
+
+    StopSending {
+        frame_type: QuicFrameTypeName,
+        stream_id: String,
+        error_code: u64,
+    },
+
+    Crypto {
+        frame_type: QuicFrameTypeName,
+        offset: String,
+        length: String,
+    },
+
+    NewToken {
+        frame_type: QuicFrameTypeName,
+        length: String,
+        token: String,
+    },
+
+    Stream {
+        frame_type: QuicFrameTypeName,
+        stream_id: String,
+        offset: String,
+        length: String,
+        fin: bool,
+
+        raw: Option<String>,
+    },
+
+    MaxData {
+        frame_type: QuicFrameTypeName,
+        maximum: String,
+    },
+
+    MaxStreamData {
+        frame_type: QuicFrameTypeName,
+        stream_id: String,
+        maximum: String,
+    },
+
+    MaxStreams {
+        frame_type: QuicFrameTypeName,
+        stream_type: StreamType,
+        maximum: String,
+    },
+
+    DataBlocked {
+        frame_type: QuicFrameTypeName,
+        limit: String,
+    },
+
+    StreamDataBlocked {
+        frame_type: QuicFrameTypeName,
+        stream_id: String,
+        limit: String,
+    },
+
+    StreamsBlocked {
+        frame_type: QuicFrameTypeName,
+        stream_type: StreamType,
+        limit: String,
+    },
+
+    NewConnectionId {
+        frame_type: QuicFrameTypeName,
+        sequence_number: String,
+        retire_prior_to: String,
+        length: u64,
+        connection_id: String,
+        reset_token: String,
+    },
+
+    RetireConnectionId {
+        frame_type: QuicFrameTypeName,
+        sequence_number: String,
+    },
+
+    PathChallenge {
+        frame_type: QuicFrameTypeName,
+
+        data: Option<String>,
+    },
+
+    PathResponse {
+        frame_type: QuicFrameTypeName,
+
+        data: Option<String>,
+    },
+
+    ConnectionClose {
+        frame_type: QuicFrameTypeName,
+        error_space: ErrorSpace,
+        error_code: u64,
+        raw_error_code: u64,
+        reason: String,
+
+        trigger_frame_type: Option<String>,
+    },
+
+    HandshakeDone {
+        frame_type: QuicFrameTypeName,
+    },
+
+    Datagram {
+        frame_type: QuicFrameTypeName,
+        length: String,
+
+        raw: Option<String>,
+    },
+
+    Unknown {
+        frame_type: QuicFrameTypeName,
+        raw_frame_type: u64,
+    },
+}
+
+impl QuicFrame {
+    pub fn padding() -> Self {
+        QuicFrame::Padding {
+            frame_type: QuicFrameTypeName::Padding,
+        }
+    }
+
+    pub fn ping() -> Self {
+        QuicFrame::Ping {
+            frame_type: QuicFrameTypeName::Ping,
+        }
+    }
+
+    pub fn ack(
+        ack_delay: Option<String>, acked_ranges: Option<Vec<(u64, u64)>>,
+        ect1: Option<String>, ect0: Option<String>, ce: Option<String>,
+    ) -> Self {
+        QuicFrame::Ack {
+            frame_type: QuicFrameTypeName::Ack,
+            ack_delay,
+            acked_ranges,
+            ect1,
+            ect0,
+            ce,
+        }
+    }
+
+    pub fn reset_stream(
+        stream_id: String, error_code: u64, final_size: String,
+    ) -> Self {
+        QuicFrame::ResetStream {
+            frame_type: QuicFrameTypeName::ResetStream,
+            stream_id,
+            error_code,
+            final_size,
+        }
+    }
+
+    pub fn stop_sending(stream_id: String, error_code: u64) -> Self {
+        QuicFrame::StopSending {
+            frame_type: QuicFrameTypeName::StopSending,
+            stream_id,
+            error_code,
+        }
+    }
+
+    pub fn crypto(offset: String, length: String) -> Self {
+        QuicFrame::Crypto {
+            frame_type: QuicFrameTypeName::Crypto,
+            offset,
+            length,
+        }
+    }
+
+    pub fn new_token(length: String, token: String) -> Self {
+        QuicFrame::NewToken {
+            frame_type: QuicFrameTypeName::NewToken,
+            length,
+            token,
+        }
+    }
+
+    pub fn stream(
+        stream_id: String, offset: String, length: String, fin: bool,
+        raw: Option<String>,
+    ) -> Self {
+        QuicFrame::Stream {
+            frame_type: QuicFrameTypeName::Stream,
+            stream_id,
+            offset,
+            length,
+            fin,
+            raw,
+        }
+    }
+
+    pub fn max_data(maximum: String) -> Self {
+        QuicFrame::MaxData {
+            frame_type: QuicFrameTypeName::MaxData,
+            maximum,
+        }
+    }
+
+    pub fn max_stream_data(stream_id: String, maximum: String) -> Self {
+        QuicFrame::MaxStreamData {
+            frame_type: QuicFrameTypeName::MaxStreamData,
+            stream_id,
+            maximum,
+        }
+    }
+
+    pub fn max_streams(stream_type: StreamType, maximum: String) -> Self {
+        QuicFrame::MaxStreams {
+            frame_type: QuicFrameTypeName::MaxStreams,
+            stream_type,
+            maximum,
+        }
+    }
+
+    pub fn data_blocked(limit: String) -> Self {
+        QuicFrame::DataBlocked {
+            frame_type: QuicFrameTypeName::DataBlocked,
+            limit,
+        }
+    }
+
+    pub fn stream_data_blocked(stream_id: String, limit: String) -> Self {
+        QuicFrame::StreamDataBlocked {
+            frame_type: QuicFrameTypeName::StreamDataBlocked,
+            stream_id,
+            limit,
+        }
+    }
+
+    pub fn streams_blocked(stream_type: StreamType, limit: String) -> Self {
+        QuicFrame::StreamsBlocked {
+            frame_type: QuicFrameTypeName::StreamsBlocked,
+            stream_type,
+            limit,
+        }
+    }
+
+    pub fn new_connection_id(
+        sequence_number: String, retire_prior_to: String, length: u64,
+        connection_id: String, reset_token: String,
+    ) -> Self {
+        QuicFrame::NewConnectionId {
+            frame_type: QuicFrameTypeName::NewConnectionId,
+            sequence_number,
+            retire_prior_to,
+            length,
+            connection_id,
+            reset_token,
+        }
+    }
+
+    pub fn retire_connection_id(sequence_number: String) -> Self {
+        QuicFrame::RetireConnectionId {
+            frame_type: QuicFrameTypeName::RetireConnectionId,
+            sequence_number,
+        }
+    }
+
+    pub fn path_challenge(data: Option<String>) -> Self {
+        QuicFrame::PathChallenge {
+            frame_type: QuicFrameTypeName::PathChallenge,
+            data,
+        }
+    }
+
+    pub fn path_response(data: Option<String>) -> Self {
+        QuicFrame::PathResponse {
+            frame_type: QuicFrameTypeName::PathResponse,
+            data,
+        }
+    }
+
+    pub fn connection_close(
+        error_space: ErrorSpace, error_code: u64, raw_error_code: u64,
+        reason: String, trigger_frame_type: Option<String>,
+    ) -> Self {
+        QuicFrame::ConnectionClose {
+            frame_type: QuicFrameTypeName::ConnectionClose,
+            error_space,
+            error_code,
+            raw_error_code,
+            reason,
+            trigger_frame_type,
+        }
+    }
+
+    pub fn handshake_done() -> Self {
+        QuicFrame::HandshakeDone {
+            frame_type: QuicFrameTypeName::HandshakeDone,
+        }
+    }
+
+    pub fn datagram(length: String, raw: Option<String>) -> Self {
+        QuicFrame::Datagram {
+            frame_type: QuicFrameTypeName::Datagram,
+            length,
+            raw,
+        }
+    }
+
+    pub fn unknown(raw_frame_type: u64) -> Self {
+        QuicFrame::Unknown {
+            frame_type: QuicFrameTypeName::Unknown,
+            raw_frame_type,
+        }
+    }
+}
+
+// ================================================================== //
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum Http3FrameTypeName {
+    Data,
+    Headers,
+    CancelPush,
+    Settings,
+    PushPromise,
+    Goaway,
+    MaxPushId,
+    DuplicatePush,
+    Reserved,
+    Unknown,
+}
+
+#[derive(Serialize, Clone)]
+pub struct HttpHeader {
+    pub name: String,
+    pub value: String,
+}
+
+#[derive(Serialize, Clone)]
+pub struct Setting {
+    pub name: String,
+    pub value: String,
+}
+
+#[derive(Serialize, Clone)]
+pub enum Http3Frame {
+    Data {
+        frame_type: Http3FrameTypeName,
+
+        raw: Option<String>,
+    },
+
+    Headers {
+        frame_type: Http3FrameTypeName,
+        headers: Vec<HttpHeader>,
+    },
+
+    CancelPush {
+        frame_type: Http3FrameTypeName,
+        push_id: String,
+    },
+
+    Settings {
+        frame_type: Http3FrameTypeName,
+        settings: Vec<Setting>,
+    },
+
+    PushPromise {
+        frame_type: Http3FrameTypeName,
+        push_id: String,
+        headers: Vec<HttpHeader>,
+    },
+
+    Goaway {
+        frame_type: Http3FrameTypeName,
+        stream_id: String,
+    },
+
+    MaxPushId {
+        frame_type: Http3FrameTypeName,
+        push_id: String,
+    },
+
+    DuplicatePush {
+        frame_type: Http3FrameTypeName,
+        push_id: String,
+    },
+
+    Reserved {
+        frame_type: Http3FrameTypeName,
+    },
+
+    Unknown {
+        frame_type: Http3FrameTypeName,
+    },
+}
+
+impl Http3Frame {
+    pub fn data(raw: Option<String>) -> Self {
+        Http3Frame::Data {
+            frame_type: Http3FrameTypeName::Data,
+            raw,
+        }
+    }
+
+    pub fn headers(headers: Vec<HttpHeader>) -> Self {
+        Http3Frame::Headers {
+            frame_type: Http3FrameTypeName::Headers,
+            headers,
+        }
+    }
+
+    pub fn cancel_push(push_id: String) -> Self {
+        Http3Frame::CancelPush {
+            frame_type: Http3FrameTypeName::CancelPush,
+            push_id,
+        }
+    }
+
+    pub fn settings(settings: Vec<Setting>) -> Self {
+        Http3Frame::Settings {
+            frame_type: Http3FrameTypeName::Settings,
+            settings,
+        }
+    }
+
+    pub fn push_promise(push_id: String, headers: Vec<HttpHeader>) -> Self {
+        Http3Frame::PushPromise {
+            frame_type: Http3FrameTypeName::PushPromise,
+            push_id,
+            headers,
+        }
+    }
+
+    pub fn goaway(stream_id: String) -> Self {
+        Http3Frame::Goaway {
+            frame_type: Http3FrameTypeName::Goaway,
+            stream_id,
+        }
+    }
+
+    pub fn max_push_id(push_id: String) -> Self {
+        Http3Frame::MaxPushId {
+            frame_type: Http3FrameTypeName::MaxPushId,
+            push_id,
+        }
+    }
+
+    pub fn duplicate_push(push_id: String) -> Self {
+        Http3Frame::DuplicatePush {
+            frame_type: Http3FrameTypeName::DuplicatePush,
+            push_id,
+        }
+    }
+
+    pub fn reserved() -> Self {
+        Http3Frame::Reserved {
+            frame_type: Http3FrameTypeName::Reserved,
+        }
+    }
+
+    pub fn unknown() -> Self {
+        Http3Frame::Unknown {
+            frame_type: Http3FrameTypeName::Unknown,
+        }
+    }
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum QpackInstructionTypeName {
+    SetDynamicTableCapacityInstruction,
+    InsertWithNameReferenceInstruction,
+    InsertWithoutNameReferenceInstruction,
+    DuplicateInstruction,
+    HeaderAcknowledgementInstruction,
+    StreamCancellationInstruction,
+    InsertCountIncrementInstruction,
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum QpackTableType {
+    Static,
+    Dynamic,
+}
+
+#[derive(Serialize, Clone)]
+pub enum QPackInstruction {
+    SetDynamicTableCapacityInstruction {
+        instruction_type: QpackInstructionTypeName,
+
+        capacity: u64,
+    },
+
+    InsertWithNameReferenceInstruction {
+        instruction_type: QpackInstructionTypeName,
+
+        table_type: QpackTableType,
+
+        name_index: u64,
+
+        huffman_encoded_value: bool,
+        value_length: u64,
+        value: String,
+    },
+
+    InsertWithoutNameReferenceInstruction {
+        instruction_type: QpackInstructionTypeName,
+
+        huffman_encoded_name: bool,
+        name_length: u64,
+        name: String,
+
+        huffman_encoded_value: bool,
+        value_length: u64,
+        value: String,
+    },
+
+    DuplicateInstruction {
+        instruction_type: QpackInstructionTypeName,
+
+        index: u64,
+    },
+
+    HeaderAcknowledgementInstruction {
+        instruction_type: QpackInstructionTypeName,
+
+        stream_id: String,
+    },
+
+    StreamCancellationInstruction {
+        instruction_type: QpackInstructionTypeName,
+
+        stream_id: String,
+    },
+
+    InsertCountIncrementInstruction {
+        instruction_type: QpackInstructionTypeName,
+
+        increment: u64,
+    },
+}
+
+#[derive(Serialize, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum QpackHeaderBlockRepresentationTypeName {
+    IndexedHeaderField,
+    LiteralHeaderFieldWithName,
+    LiteralHeaderFieldWithoutName,
+}
+
+#[derive(Serialize, Clone)]
+pub enum QpackHeaderBlockRepresentation {
+    IndexedHeaderField {
+        header_field_type: QpackHeaderBlockRepresentationTypeName,
+
+        table_type: QpackTableType,
+        index: u64,
+
+        is_post_base: Option<bool>,
+    },
+
+    LiteralHeaderFieldWithName {
+        header_field_type: QpackHeaderBlockRepresentationTypeName,
+
+        preserve_literal: bool,
+        table_type: QpackTableType,
+        name_index: u64,
+
+        huffman_encoded_value: bool,
+        value_length: u64,
+        value: String,
+
+        is_post_base: Option<bool>,
+    },
+
+    LiteralHeaderFieldWithoutName {
+        header_field_type: QpackHeaderBlockRepresentationTypeName,
+
+        preserve_literal: bool,
+        table_type: QpackTableType,
+        name_index: u64,
+
+        huffman_encoded_name: bool,
+        name_length: u64,
+        name: String,
+
+        huffman_encoded_value: bool,
+        value_length: u64,
+        value: String,
+
+        is_post_base: Option<bool>,
+    },
+}
+
+pub struct HexSlice<'a>(&'a [u8]);
+
+impl<'a> HexSlice<'a> {
+    pub fn new<T>(data: &'a T) -> HexSlice<'a>
+    where
+        T: ?Sized + AsRef<[u8]> + 'a,
+    {
+        HexSlice(data.as_ref())
+    }
+
+    pub fn maybe_string<T>(data: Option<&'a T>) -> Option<String>
+    where
+        T: ?Sized + AsRef<[u8]> + 'a,
+    {
+        match data {
+            Some(d) => Some(format!("{}", HexSlice::new(d))),
+
+            None => None,
+        }
+    }
+}
+
+impl<'a> std::fmt::Display for HexSlice<'a> {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        for byte in self.0 {
+            write!(f, "{:02x}", byte)?;
+        }
+        Ok(())
+    }
+}
+
+#[doc(hidden)]
+pub mod testing {
+    use super::*;
+
+    pub fn make_pkt_hdr() -> PacketHeader {
+        let scid = [0x7e, 0x37, 0xe4, 0xdc, 0xc6, 0x68, 0x2d, 0xa8];
+        let dcid = [0x36, 0xce, 0x10, 0x4e, 0xee, 0x50, 0x10, 0x1c];
+
+        PacketHeader::new(
+            0,
+            Some(1251),
+            Some(1224),
+            Some(0xff00_0018),
+            Some(&scid),
+            Some(&dcid),
+        )
+    }
+
+    pub fn make_trace() -> Trace {
+        Trace::new(
+            VantagePoint {
+                name: None,
+                ty: VantagePointType::Server,
+                flow: None,
+            },
+            Some("Quiche qlog trace".to_string()),
+            Some("Quiche qlog trace description".to_string()),
+            Some(Configuration {
+                time_offset: Some("0".to_string()),
+                time_units: Some(TimeUnits::Ms),
+                original_uris: None,
+            }),
+            None,
+        )
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use testing::*;
+
+    #[test]
+    fn packet_header() {
+        let pkt_hdr = make_pkt_hdr();
+
+        let log_string = r#"{
+  "packet_number": "0",
+  "packet_size": 1251,
+  "payload_length": 1224,
+  "version": "ff000018",
+  "scil": "8",
+  "dcil": "8",
+  "scid": "7e37e4dcc6682da8",
+  "dcid": "36ce104eee50101c"
+}"#;
+
+        assert_eq!(serde_json::to_string_pretty(&pkt_hdr).unwrap(), log_string);
+    }
+
+    #[test]
+    fn packet_sent_event_no_frames() {
+        let log_string = r#"{
+  "packet_type": "initial",
+  "header": {
+    "packet_number": "0",
+    "packet_size": 1251,
+    "payload_length": 1224,
+    "version": "ff00001b",
+    "scil": "8",
+    "dcil": "8",
+    "scid": "7e37e4dcc6682da8",
+    "dcid": "36ce104eee50101c"
+  }
+}"#;
+
+        let scid = [0x7e, 0x37, 0xe4, 0xdc, 0xc6, 0x68, 0x2d, 0xa8];
+        let dcid = [0x36, 0xce, 0x10, 0x4e, 0xee, 0x50, 0x10, 0x1c];
+        let pkt_hdr = PacketHeader::new(
+            0,
+            Some(1251),
+            Some(1224),
+            Some(0xff00001b),
+            Some(&scid),
+            Some(&dcid),
+        );
+
+        let pkt_sent_evt = EventData::PacketSent {
+            raw_encrypted: None,
+            raw_decrypted: None,
+            packet_type: PacketType::Initial,
+            header: pkt_hdr.clone(),
+            frames: None,
+            is_coalesced: None,
+        };
+
+        assert_eq!(
+            serde_json::to_string_pretty(&pkt_sent_evt).unwrap(),
+            log_string
+        );
+    }
+
+    #[test]
+    fn packet_sent_event_some_frames() {
+        let log_string = r#"{
+  "packet_type": "initial",
+  "header": {
+    "packet_number": "0",
+    "packet_size": 1251,
+    "payload_length": 1224,
+    "version": "ff000018",
+    "scil": "8",
+    "dcil": "8",
+    "scid": "7e37e4dcc6682da8",
+    "dcid": "36ce104eee50101c"
+  },
+  "frames": [
+    {
+      "frame_type": "padding"
+    },
+    {
+      "frame_type": "ping"
+    },
+    {
+      "frame_type": "stream",
+      "stream_id": "0",
+      "offset": "0",
+      "length": "100",
+      "fin": true
+    }
+  ]
+}"#;
+
+        let pkt_hdr = make_pkt_hdr();
+
+        let mut frames = Vec::new();
+        frames.push(QuicFrame::padding());
+
+        frames.push(QuicFrame::ping());
+
+        frames.push(QuicFrame::stream(
+            "0".to_string(),
+            "0".to_string(),
+            "100".to_string(),
+            true,
+            None,
+        ));
+
+        let pkt_sent_evt = EventData::PacketSent {
+            raw_encrypted: None,
+            raw_decrypted: None,
+            packet_type: PacketType::Initial,
+            header: pkt_hdr.clone(),
+            frames: Some(frames),
+            is_coalesced: None,
+        };
+
+        assert_eq!(
+            serde_json::to_string_pretty(&pkt_sent_evt).unwrap(),
+            log_string
+        );
+    }
+
+    #[test]
+    fn trace_no_events() {
+        let log_string = r#"{
+  "vantage_point": {
+    "type": "server"
+  },
+  "title": "Quiche qlog trace",
+  "description": "Quiche qlog trace description",
+  "configuration": {
+    "time_units": "ms",
+    "time_offset": "0"
+  },
+  "event_fields": [
+    "relative_time",
+    "category",
+    "event",
+    "data"
+  ],
+  "events": []
+}"#;
+
+        let trace = make_trace();
+
+        assert_eq!(serde_json::to_string_pretty(&trace).unwrap(), log_string);
+    }
+
+    #[test]
+    fn trace_single_transport_event() {
+        let log_string = r#"{
+  "vantage_point": {
+    "type": "server"
+  },
+  "title": "Quiche qlog trace",
+  "description": "Quiche qlog trace description",
+  "configuration": {
+    "time_units": "ms",
+    "time_offset": "0"
+  },
+  "event_fields": [
+    "relative_time",
+    "category",
+    "event",
+    "data"
+  ],
+  "events": [
+    [
+      "0",
+      "transport",
+      "packet_sent",
+      {
+        "packet_type": "initial",
+        "header": {
+          "packet_number": "0",
+          "packet_size": 1251,
+          "payload_length": 1224,
+          "version": "ff000018",
+          "scil": "8",
+          "dcil": "8",
+          "scid": "7e37e4dcc6682da8",
+          "dcid": "36ce104eee50101c"
+        },
+        "frames": [
+          {
+            "frame_type": "stream",
+            "stream_id": "0",
+            "offset": "0",
+            "length": "100",
+            "fin": true
+          }
+        ]
+      }
+    ]
+  ]
+}"#;
+
+        let mut trace = make_trace();
+
+        let pkt_hdr = make_pkt_hdr();
+
+        let frames = vec![QuicFrame::stream(
+            "0".to_string(),
+            "0".to_string(),
+            "100".to_string(),
+            true,
+            None,
+        )];
+        let event = event::Event::packet_sent_min(
+            PacketType::Initial,
+            pkt_hdr,
+            Some(frames),
+        );
+
+        trace.push_event(std::time::Duration::new(0, 0), event);
+
+        assert_eq!(serde_json::to_string_pretty(&trace).unwrap(), log_string);
+    }
+
+    #[test]
+    fn test_event_validity() {
+        // Test a single event in each category
+
+        let ev = event::Event::server_listening_min(443, 443);
+        assert!(ev.is_valid());
+
+        let ev = event::Event::transport_parameters_set_min();
+        assert!(ev.is_valid());
+
+        let ev = event::Event::recovery_parameters_set_min();
+        assert!(ev.is_valid());
+
+        let ev = event::Event::h3_parameters_set_min();
+        assert!(ev.is_valid());
+
+        let ev = event::Event::qpack_state_updated_min();
+        assert!(ev.is_valid());
+
+        let ev = event::Event {
+            category: EventCategory::Error,
+            ty: EventType::GenericEventType(GenericEventType::ConnectionError),
+            data: EventData::ConnectionError {
+                code: None,
+                description: None,
+            },
+        };
+
+        assert!(ev.is_valid());
+    }
+
+    #[test]
+    fn bogus_event_validity() {
+        // Test a single event in each category
+
+        let mut ev = event::Event::server_listening_min(443, 443);
+        ev.category = EventCategory::Simulation;
+        assert!(!ev.is_valid());
+
+        let mut ev = event::Event::transport_parameters_set_min();
+        ev.category = EventCategory::Simulation;
+        assert!(!ev.is_valid());
+
+        let mut ev = event::Event::recovery_parameters_set_min();
+        ev.category = EventCategory::Simulation;
+        assert!(!ev.is_valid());
+
+        let mut ev = event::Event::h3_parameters_set_min();
+        ev.category = EventCategory::Simulation;
+        assert!(!ev.is_valid());
+
+        let mut ev = event::Event::qpack_state_updated_min();
+        ev.category = EventCategory::Simulation;
+        assert!(!ev.is_valid());
+
+        let ev = event::Event {
+            category: EventCategory::Error,
+            ty: EventType::GenericEventType(GenericEventType::ConnectionError),
+            data: EventData::FramesProcessed { frames: Vec::new() },
+        };
+
+        assert!(!ev.is_valid());
+    }
+
+    #[test]
+    fn serialization_states() {
+        let v: Vec<u8> = Vec::new();
+        let buff = std::io::Cursor::new(v);
+        let writer = Box::new(buff);
+
+        let mut trace = make_trace();
+        let pkt_hdr = make_pkt_hdr();
+
+        let frame1 = QuicFrame::stream(
+            "40".to_string(),
+            "40".to_string(),
+            "400".to_string(),
+            true,
+            None,
+        );
+
+        let event1 = event::Event::packet_sent_min(
+            PacketType::Handshake,
+            pkt_hdr.clone(),
+            Some(vec![frame1]),
+        );
+
+        trace.push_event(std::time::Duration::new(0, 0), event1);
+
+        let frame2 = QuicFrame::stream(
+            "0".to_string(),
+            "0".to_string(),
+            "100".to_string(),
+            true,
+            None,
+        );
+
+        let frame3 = QuicFrame::stream(
+            "0".to_string(),
+            "0".to_string(),
+            "100".to_string(),
+            true,
+            None,
+        );
+
+        let event2 = event::Event::packet_sent_min(
+            PacketType::Initial,
+            pkt_hdr.clone(),
+            Some(Vec::new()),
+        );
+
+        let event3 = event::Event::packet_sent(
+            PacketType::Initial,
+            pkt_hdr,
+            Some(Vec::new()),
+            None,
+            Some("encrypted_foo".to_string()),
+            Some("decrypted_foo".to_string()),
+        );
+
+        let mut s = QlogStreamer::new(
+            "version".to_string(),
+            Some("title".to_string()),
+            Some("description".to_string()),
+            None,
+            std::time::Instant::now(),
+            trace,
+            writer,
+        );
+
+        // Before the log is started all other operations should fail.
+        assert!(match s.add_event(event2.clone()) {
+            Err(Error::InvalidState) => true,
+            _ => false,
+        });
+        assert!(match s.add_frame(frame2.clone(), false) {
+            Err(Error::InvalidState) => true,
+            _ => false,
+        });
+        assert!(match s.finish_frames() {
+            Err(Error::InvalidState) => true,
+            _ => false,
+        });
+        assert!(match s.finish_log() {
+            Err(Error::InvalidState) => true,
+            _ => false,
+        });
+
+        // Once a log is started, can't write frames before an event.
+        assert!(match s.start_log() {
+            Ok(()) => true,
+            _ => false,
+        });
+        assert!(match s.add_frame(frame2.clone(), true) {
+            Err(Error::InvalidState) => true,
+            _ => false,
+        });
+        assert!(match s.finish_frames() {
+            Err(Error::InvalidState) => true,
+            _ => false,
+        });
+
+        // Some events hold frames; can't write any more events until frame
+        // writing is concluded.
+        assert!(match s.add_event(event2.clone()) {
+            Ok(true) => true,
+            _ => false,
+        });
+        assert!(match s.add_event(event2.clone()) {
+            Err(Error::InvalidState) => true,
+            _ => false,
+        });
+
+        // While writing frames, can't write events.
+        assert!(match s.add_frame(frame2.clone(), false) {
+            Ok(()) => true,
+            _ => false,
+        });
+
+        assert!(match s.add_event(event2.clone()) {
+            Err(Error::InvalidState) => true,
+            _ => false,
+        });
+        assert!(match s.finish_frames() {
+            Ok(()) => true,
+            _ => false,
+        });
+
+        // Adding an event that includes both frames and raw data should
+        // be allowed.
+        assert!(match s.add_event(event3.clone()) {
+            Ok(true) => true,
+            _ => false,
+        });
+        assert!(match s.add_frame(frame3.clone(), false) {
+            Ok(()) => true,
+            _ => false,
+        });
+        assert!(match s.finish_frames() {
+            Ok(()) => true,
+            _ => false,
+        });
+
+        assert!(match s.finish_log() {
+            Ok(()) => true,
+            _ => false,
+        });
+
+        let r = s.writer();
+        let w: &Box<std::io::Cursor<Vec<u8>>> = unsafe { std::mem::transmute(r) };
+
+        let log_string = r#"{"qlog_version":"version","title":"title","description":"description","traces":[{"vantage_point":{"type":"server"},"title":"Quiche qlog trace","description":"Quiche qlog trace description","configuration":{"time_units":"ms","time_offset":"0"},"event_fields":["relative_time","category","event","data"],"events":[["0","transport","packet_sent",{"packet_type":"handshake","header":{"packet_number":"0","packet_size":1251,"payload_length":1224,"version":"ff000018","scil":"8","dcil":"8","scid":"7e37e4dcc6682da8","dcid":"36ce104eee50101c"},"frames":[{"frame_type":"stream","stream_id":"40","offset":"40","length":"400","fin":true}]}],["0","transport","packet_sent",{"packet_type":"initial","header":{"packet_number":"0","packet_size":1251,"payload_length":1224,"version":"ff000018","scil":"8","dcil":"8","scid":"7e37e4dcc6682da8","dcid":"36ce104eee50101c"},"frames":[{"frame_type":"stream","stream_id":"0","offset":"0","length":"100","fin":true}]}],["0","transport","packet_sent",{"packet_type":"initial","header":{"packet_number":"0","packet_size":1251,"payload_length":1224,"version":"ff000018","scil":"8","dcil":"8","scid":"7e37e4dcc6682da8","dcid":"36ce104eee50101c"},"raw_encrypted":"encrypted_foo","raw_decrypted":"decrypted_foo","frames":[{"frame_type":"stream","stream_id":"0","offset":"0","length":"100","fin":true}]}]]}]}"#;
+
+        let written_string = std::str::from_utf8(w.as_ref().get_ref()).unwrap();
+
+        assert_eq!(log_string, written_string);
+    }
+}
+
+pub mod event;