code: func (nc *Conn) removeFlushEntry(ch chan struct{}) bool {
  	nc.mu.Lock()
  	defer nc.mu.Unlock()
  	if nc.pongs == nil {
  		return false
  	}
  	for i, c := range nc.pongs {
  		if c == ch {
  			nc.pongs[i] = nil
  			return true
  		}
  	}
  	return false
  }
docs: // FIXME: This is a hack
  // removeFlushEntry is needed when we need to discard queued up responses
  // for our pings as part of a flush call. This happens when we have a flush
  // call outstanding and we call close.