2.1.4:
* Values are now correctly returned from sync_to_async and async_to_sync
* ASGI_THREADS environment variable now works correctly
2.1.3:
* Add an ApplicationCommunicator.wait() method to allow you to wait for an
application instance to exit before seeing what it did.
2.1.2:
* Allow AsyncToSync to work if called from a non-async-wrapped sync context.
2.1.1:
* Allow AsyncToSync constructor to be called inside SyncToAsync.
2.0.1:
* Bugfix release to have HTTP response content message as the correct
"http.response.content" not the older "http.response.chunk".
2.0.0:
* Complete rewrite for new async-based ASGI mechanisms and removal of
channel layers.
