pubsub :: async_receive2 hangs forever in sentinel mode

hi,
in sentinel mode, the connection is normally recovered for `async_exec()` . But not for `async_receive2`.

is there a plan to add the recovery with auto subscribe?

Start by reproducing the `async_receive2` hang in sentinel mode and compare its recovery behavior with `async_exec()`. Trace how reconnection and subscription restoration are handled for both entry points; done means `async_receive2` recovers and automatically resubscribes after the connection is recovered.

Written by the indexing model from the issue text.