Retransmitter reset does not prevent new task addition after chanel close

Sometimes, messages are being added to the Retransmitter after a channel has been closed. This can happen if OOB messages are being passed around at the time a channel is leaving a group. The problem occurs in that messages are added after Retransmitter.reset(). Normally, the timer is also stopped when the channel is disconnected, but since the Timer is shared amongst all channels, any messages added to Retransmitter after reset() just continue to be requested because the timer that those tasks were scheduled on did not die.

This can be solved by either specifically stopping the Retransmitter or giving each ProtocolAdapter their own Timer which is then shutdown on channel disconnect.

Michael