The reactor runs 2 go-routines for each added peer: gossipDataRoutine and gossipVotesRoutine.
The consensus state runs two persistent go-routines: timeoutRoutine and receiveRoutine. Go-routines are also started to trigger timeouts and to avoid blocking when the internalMsgQueue is really backed up.
A write-ahead log is used to record all messages processed by the receiveRoutine, which amounts to all inputs to the consensus state machine: messages from peers, messages from ourselves, and timeouts. They can be played back deterministically at startup or using the replay console.