code: func (b *eventListenerSupport) fire(message string) {
  	b.Lock()
  	defer b.Unlock()
  	for substr, listeners := range b.listeners {
  		if strings.Contains(message, substr) {
  			for _, listener := range listeners {
  				listener <- message
  			}
  		}
  	}
  }
docs: // fire sends the specified message to each listener that is registered with
  // a substring contained in the message