Function read_msg 

pub(crate) async fn read_msg<T>(
    stream_id: UniqId,
    stream: impl Stream<Item = Result<AnyChanCell>> + Unpin,
) -> Result<T>
where
    T: RestrictedMsg + TryFrom<AnyChanMsg, Error = AnyChanMsg>,

Read a message from the stream.

The expecting parameter is used for logging purposes, not filtering.