Deprecate the OptionalReceiver

Signed-off-by: Sahas Subramanian <[email protected]>

Author: shsms

RELEASE_NOTES.md

@@ -12,6 +12,13 @@
 
 - An experimental `NopReceiver` implementation has been added, which can be used as a place-holder receiver that never receives a message.
 
+- The experimental `OptionalReceiver` has been deprecated.  It will be removed with the next major release.  It can be replaced with a `NopReceiver` as follows:
+
+  ```python
+  opt_recv: Receiver[T] | None
+  recv: Receiver[T] = NopReceiver[T]() if opt_recv is None else opt_recv
+  ```
+
 ## Bug Fixes
 
 <!-- Here goes notable bug fixes that are worth a special mention or explanation -->

src/frequenz/channels/experimental/_optional_receiver.py

@@ -10,11 +10,12 @@
 
 import asyncio
 
-from typing_extensions import override
+from typing_extensions import deprecated, override
 
 from frequenz.channels import Receiver, ReceiverError, ReceiverMessageT_co
 
 
+@deprecated("Use `frequenz.channels.experimental.NopReceiver` instead.")
 class OptionalReceiver(Receiver[ReceiverMessageT_co]):
     """A receiver that will wait indefinitely if there is no underlying receiver.