libasync: add mod delay

libasync/src/delay.rs

@@ -0,0 +1,7 @@
+use embedded_hal::timer::CountDown;
+use crate::block_async;
+
+pub async fn delay<T: CountDown<Time=C>, C>(timer: &mut T, count: C) {
+    timer.start(count);
+    let _ = block_async!(timer.wait()).await;
+}