Function finish_read 

async fn finish_read<S>(
    socket: &mut ClientSocket<S>,
    state: &Arc<TransportState>,
    watching: &mut Watching,
    holds: &mut Holds<'_>,
    reads: &mut Option<Reading>,
    held: &mut Batch,
    done: ReadAnswer,
) -> Result<()>
where
    S: Sink<Message, Error = Error> + Unpin + Send,

Answer a subscribe read that ran off the loop: its record, its refusal, or nothing when the client let the seat go while it ran.