Added untested comm impl

orchid-base/src/stash.rs

@@ -0,0 +1,42 @@
+//! A pattern for running async code from sync destructors and other
+//! unfortunately sync callbacks
+//!
+//! We create a task_local
+
+use std::collections::VecDeque;
+use std::pin::Pin;
+
+use some_executor::task_local;
+
+#[derive(Default)]
+struct StashedFutures {
+	queue: VecDeque<Pin<Box<dyn Future<Output = ()>>>>,
+}
+
+task_local! {
+	static STASHED_FUTURES: StashedFutures;
+}
+
+/// Complete the argument future, and any futures spawned from it via [stash].
+/// This is useful mostly to guarantee that messaging destructors have run.
+pub async fn with_stash<F: Future>(fut: F) -> F::Output {
+	STASHED_FUTURES
+		.scope(StashedFutures::default(), async {
+			let val = fut.await;
+			while let Some(fut) = STASHED_FUTURES.with_mut(|sf| sf.unwrap().queue.pop_front()) {
+				fut.await;
+			}
+			val
+		})
+		.await
+}
+
+/// Schedule a future to be run before the next [with_stash] guard ends. This is
+/// most useful for sending messages from destructors.
+pub fn stash<F: Future + 'static>(fut: F) {
+	STASHED_FUTURES.with_mut(|sf| {
+		sf.expect("No stash! Timely completion cannot be guaranteed").queue.push_back(Box::pin(async {
+			fut.await;
+		}))
+	})
+}