Scenario:
1. Two messages were read from the connection `p.conn`
2. The first message has started to be processed
3. The second message was queued to be added to the channel `p.incoming`
4. Processing of the first message failed with an error
5. TCP peer is closed, but processing of the second message continues
Signed-off-by: Dmitrii Stepanov <dima-stepan@yandex.ru>