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diff --git a/third_party/rust/glean/tests/overflowing_preinit.rs b/third_party/rust/glean/tests/overflowing_preinit.rs
new file mode 100644
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+++ b/third_party/rust/glean/tests/overflowing_preinit.rs
@@ -0,0 +1,88 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+//! This integration test should model how the RLB is used when embedded in another Rust application
+//! (e.g. FOG/Firefox Desktop).
+//!
+//! We write a single test scenario per file to avoid any state keeping across runs
+//! (different files run as different processes).
+
+mod common;
+
+use glean::ConfigurationBuilder;
+
+/// Some user metrics.
+mod metrics {
+    use glean::private::*;
+    use glean::Lifetime;
+    use glean_core::CommonMetricData;
+    use once_cell::sync::Lazy;
+
+    #[allow(non_upper_case_globals)]
+    pub static rapid_counting: Lazy<CounterMetric> = Lazy::new(|| {
+        CounterMetric::new(CommonMetricData {
+            name: "rapid_counting".into(),
+            category: "sample".into(),
+            send_in_pings: vec!["metrics".into()],
+            lifetime: Lifetime::Ping,
+            disabled: false,
+            ..Default::default()
+        })
+    });
+
+    // This is a hack, but a good one:
+    //
+    // To avoid reaching into RLB internals we re-create the metric so we can look at it.
+    #[allow(non_upper_case_globals)]
+    pub static preinit_tasks_overflow: Lazy<CounterMetric> = Lazy::new(|| {
+        CounterMetric::new(CommonMetricData {
+            category: "glean.error".into(),
+            name: "preinit_tasks_overflow".into(),
+            send_in_pings: vec!["metrics".into()],
+            lifetime: Lifetime::Ping,
+            disabled: false,
+            ..Default::default()
+        })
+    });
+}
+
+/// Test scenario: Lots of metric recordings before  init.
+///
+/// The app starts recording metrics before Glean is initialized.
+/// Once initialized the recordings are processed and data is persisted.
+/// The pre-init dispatcher queue records how many recordings over the limit it saw.
+///
+/// This is an integration test to avoid dealing with resetting the dispatcher.
+#[test]
+fn overflowing_the_task_queue_records_telemetry() {
+    common::enable_test_logging();
+
+    // Create a custom configuration to use a validating uploader.
+    let dir = tempfile::tempdir().unwrap();
+    let tmpname = dir.path().to_path_buf();
+
+    let cfg = ConfigurationBuilder::new(true, tmpname, "firefox-desktop")
+        .with_server_endpoint("invalid-test-host")
+        .build();
+
+    // Insert a bunch of tasks to overflow the queue.
+    for _ in 0..1010 {
+        metrics::rapid_counting.add(1);
+    }
+
+    // Now initialize Glean
+    common::initialize(cfg);
+
+    assert_eq!(Some(1000), metrics::rapid_counting.test_get_value(None));
+
+    // The metrics counts the total number of overflowing tasks,
+    // (and the count of tasks in the queue when we overflowed: bug 1764573)
+    // this might include Glean-internal tasks.
+    let val = metrics::preinit_tasks_overflow
+        .test_get_value(None)
+        .unwrap();
+    assert!(val >= 10);
+
+    glean::shutdown();
+}