func (c *Conn) updateSerial(msg *proto.ProtocolMessage, listen chan<- error) { const maxint64 = 1<<63 - 1 msg.MsgSerial = c.msgSerial c.msgSerial = (c.msgSerial + 1) % maxint64 if listen != nil { c.pending.Enqueue(msg.MsgSerial, listen) } }