1 files changed, 48 insertions, 0 deletions
diff --git a/third_party/rust/async-task/examples/spawn.rs b/third_party/rust/async-task/examples/spawn.rs
new file mode 100644
index 0000000000..3a648114c9
--- /dev/null
+++ b/third_party/rust/async-task/examples/spawn.rs
@@ -0,0 +1,48 @@
+//! A simple single-threaded executor.
+
+use std::future::Future;
+use std::panic::catch_unwind;
+use std::thread;
+
+use async_task::{Runnable, Task};
+use once_cell::sync::Lazy;
+use smol::future;
+
+/// Spawns a future on the executor.
+fn spawn<F, T>(future: F) -> Task<T>
+where
+    F: Future<Output = T> + Send + 'static,
+    T: Send + 'static,
+{
+    // A queue that holds scheduled tasks.
+    static QUEUE: Lazy<flume::Sender<Runnable>> = Lazy::new(|| {
+        let (sender, receiver) = flume::unbounded::<Runnable>();
+
+        // Start the executor thread.
+        thread::spawn(|| {
+            for runnable in receiver {
+                // Ignore panics inside futures.
+                let _ignore_panic = catch_unwind(|| runnable.run());
+            }
+        });
+
+        sender
+    });
+
+    // Create a task that is scheduled by pushing it into the queue.
+    let schedule = |runnable| QUEUE.send(runnable).unwrap();
+    let (runnable, task) = async_task::spawn(future, schedule);
+
+    // Schedule the task by pushing it into the queue.
+    runnable.schedule();
+
+    task
+}
+
+fn main() {
+    // Spawn a future and await its result.
+    let task = spawn(async {
+        println!("Hello, world!");
+    });
+    future::block_on(task);
+}