code: func (c *connection) releaseWaiter(correlationID int32) {
  	c.mu.Lock()
  	rc, ok := c.respc[correlationID]
  	if ok {
  		delete(c.respc, correlationID)
  		close(rc)
  	}
  	c.mu.Unlock()
  }
docs: // releaseWaiter removes response channel from waiters pool and close it.
  // Calling this method for unknown correlationID has no effect.