"Task has lost its waker" and freeze when sending large packets

When sending large packets very quickly, there is a chance the future completely locks up and loses its waker according to `tokio-console` and `console-subscriber`. I am using `rustc 1.86.0-nightly (1e9b0177d 2025-01-24)` Reproduction code: ```toml [package] name = "tokio-ws-reproduce" version = "0.1.0" edition = "2021" [dependencies] bytes = "1.9.0" console-subscriber = "0.4.1" futures = { version = "0.3.31", default-features = false, features = ["std", "async-await"] } tokio = { version = "1.43.0", features = ["full"] } tokio-websockets = { version = "0.11.0", features = ["client", "simd", "sha1_smol", "rand", "native-tls"] } ``` ```rust use bytes::Bytes; use futures::{SinkExt, StreamExt, future::join}; use tokio_websockets::Message; #[tokio::main] async fn main() { console_subscriber::init(); let (mut tx, mut rx) = tokio_websockets::ClientBuilder::new() .uri("ws://127.0.0.1:3000") .unwrap() .connect() .await .unwrap() .0 .split(); let len = std::env::args().nth(1).unwrap().parse().unwrap(); let a = tokio::spawn(async move { let x = Bytes::from(vec![0; len]); let mut cnt = 0usize; loop { let x = Message::binary(x.clone()); tx.send(x).await.unwrap(); println!("sent {cnt}"); cnt += 1; } }); let b = tokio::spawn(async move { loop { rx.next().await; } }); join(a, b).await.0.unwrap(); } ``` Run the echo-server example from this repo (commit b8b3418): `cargo r -r --example echo_server -F server,sha1_smol` Then run the code: `RUSTFLAGS='--cfg tokio_unstable' cargo r -r -- 51205` On my machine, it locks up after around 100-150 messages with a size of `51205`. It also locks up with smaller message sizes, but not quickly or reliably. Once it locks up, check tokio-console:   The task location matches up with the `tokio::spawn` for the writer task.