sync: support mpsc send with `&self` (#2861)

Updates the mpsc channel to use the intrusive waker based sempahore.
This enables using `Sender` with `&self`.

Instead of using `Sender::poll_ready` to ensure capacity and updating
the `Sender` state, `async fn Sender::reserve()` is added. This function
returns a `Permit` value representing the reserved capacity.

Fixes: #2637
Refs: #2718 (intrusive waiters)

1 files changed, 0 insertions, 2 deletions

diff --git a/tokio/src/sync/tests/mod.rs b/tokio/src/sync/tests/mod.rs
index c637cb6b..a78be6f3 100644
--- a/tokio/src/sync/tests/mod.rs
+++ b/tokio/src/sync/tests/mod.rs
@@ -1,6 +1,5 @@
 cfg_not_loom! {
     mod atomic_waker;
-    mod semaphore_ll;
     mod semaphore_batch;
 }
 
@@ -12,6 +11,5 @@ cfg_loom! {
     mod loom_notify;
     mod loom_oneshot;
     mod loom_semaphore_batch;
-    mod loom_semaphore_ll;
     mod loom_watch;
 }