Filebat signals

[elastic_user1]

I noticed following in my log when i could not connect to Logstash logs:

    NFO        pipeline/output.go:93        Attempting to reconnect to backoff(async()) with 3 reconnect attempt(s)
    NFO        [publisher]        pipeline/retry.go:173        retryer: send wait signal to consumer
    NFO        [publisher]        pipeline/retry.go:175          done
    RROR        pipeline/output.go:100        Failed to connect to backoff(async()): dial tcp connect: connection refused
    NFO        pipeline/output.go:93        Attempting to reconnect to backoff(async()) with 4 reconnect attempt(s)
    NFO        [publisher]        pipeline/retry.go:196        retryer: send unwait-signal to consumer
    NFO        [publisher]        pipeline/retry.go:198          done
    NFO        [publisher]        pipeline/retry.go:173        retryer: send wait signal to consumer
    NFO        [publisher]        pipeline/retry.go:175          done
    RROR        pipeline/output.go:100        Failed to connect to backoff(async()): dial connect: connection refused
    NFO        pipeline/output.go:93        Attempting to reconnect to backoff(async()) with 5 reconnect attempt(s)
    NFO        [publisher]        pipeline/retry.go:196        retryer: send unwait-signal to consumer
    NFO        [publisher]        pipeline/retry.go:198          done
    NFO        [publisher]        pipeline/retry.go:173        retryer: send wait signal to consumer
    NFO        [publisher]        pipeline/retry.go:175          done
    //RROR        pipeline/output.go:100        Failed to connect to backoff(async()): dial tcp connect: //connection refused
    //NFO        pipeline/output.go:93        Attempting to reconnect to backoff(async()) with 6 reconnect //attempt(s)
    //NFO        [publisher]        pipeline/retry.go:196        retryer: send unwait-signal to consumer
    //NFO        [publisher]        pipeline/retry.go:198          done
    //NFO        [publisher]        pipeline/retry.go:173        retryer: send wait signal to consumer
    //NFO        [publisher]        pipeline/retry.go:175          done
    //

I am confused, that right after an unwait signal is set, a wait signal is set at once. Why did unwait and wait signal happen?

I don't know Go, so it is not clear to me.

I examined the source code, i saw that wait and unwait signals link to SigHint()

//func (c *eventConsumer) sigWait() {
//  c.wait.Store(true)
// c.sigHint()
//}

//func (c *eventConsumer) sigUnWait() {
//  c.wait.Store(false)
//  c.sigHint()


//func (c *eventConsumer) sigHint() {
  // send signal to unblock a consumer trying to publish events.
  // With flags being set atomically, multiple signals can be compressed into one
  // signal -> drop if queue is not empty
 // select {
 // case c.sig <- consumerSignal{tag: sigConsumerCheck}:
 // default:
 // }

I am not sure what sigConsumerCheck contains in my situation.

I debugged Filebeat and saw that the queue has ~2*max_bulk_setting (default 2048) (in my situation it was "events":{"active":4117}}), any more events doesn't add and it is ok. Events in the queue were kept until the connect was established.
So I didn't understand what happened when i had unwait/wait signal.