Update changelog

Author: ivmarkov

CHANGELOG.md

@@ -5,6 +5,17 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+* Potential fix for #3 (long running futures eventually stall):
+  * Background:
+    * Turns out this is likely related to ALL executor queues used by this crate (`crossbeam-queue`, `heapless MPMC`) being incompatible with OSes spawning threads at different priorities (since these queues do not use the OS mutexes, they are amenable to priority inversion issues - https://github.com/crossbeam-rs/crossbeam/issues/675#issuecomment-4003522816)
+    * Note that very likely [`async-executor`](https://github.com/smol-rs/async-executor) is also affected, as it uses `concurrent-queue`, which has the same issue
+    * For more tetails, check https://github.com/esp-rs/esp-idf-svc/issues/630
+  * Solution:
+    * Use our own queue based on a mutex + `alloc::VeqDeque` (unbounded) or `heapless::Deque` (bounded)
+    * Since the queue is now protected by a mutex (via `embassy-sync`) - as long as the mutex is the OS/Platform one - and it is by default - there should be no priority inversion issues anymore
+    * Furter, allow the user to plug her own executor queue, via the new `ExecutorQueue` trait
+
 ## [0.4.1] - 2023-11-09
 * Update to heapless 0.8, and use heapless `MpMcQueue` for targets that do not have atomics, as `crossbeam` does not support such targets yet