Method flusher

nats.go:3971–4016

flusher is a separate Go routine that will process flush requests for the write bufio. This allows coalescing of writes to the underlying socket.

()

// flusher is a separate Go routine that will process flush requests for the write
// bufio. This allows coalescing of writes to the underlying socket.
func (nc *Conn) flusher() {
	// Release the wait group
	defer nc.wg.Done()

	// snapshot the bw and conn since they can change from underneath of us.
	nc.mu.Lock()
	bw := nc.bw
	conn := nc.conn
	fch := nc.fch
	nc.mu.Unlock()

	if conn == nil || bw == nil {
		return
	}

	for {
		if _, ok := <-fch; !ok {
			return
		}
		nc.mu.Lock()

		// Check to see if we should bail out.
		if !nc.isConnected() || nc.isConnecting() || conn != nc.conn {
			nc.mu.Unlock()
			return
		}
		if bw.buffered() > 0 {
			if err := bw.flush(); err != nil {
				if nc.err == nil {
					nc.err = err
				}
				if asyncErrorCB := nc.Opts.AsyncErrorCB; asyncErrorCB != nil {
					nc.ach.push(func() { asyncErrorCB(nc, nil, err) })
				}
				if nc.Opts.ReconnectOnFlusherError {
					nc.mu.Unlock()
					if shouldClose := nc.processOpErr(err, true); shouldClose {
						nc.close(CLOSED, true, nil)
					}
					return
				}
			}
		}
		nc.mu.Unlock()
	}
}

// processPing will send an immediate pong protocol response to the
// server. The server uses this mechanism to detect dead clients.