src/Events/EventEmitter.php
/**
	 * Binds the callback function to be executed the next time the channel is invoked, after which the
	 * binding will be destroyed and the callback will no longer be invoked.
	 *
	 * @param string $channel Event channel.
	 * @param callable $callback Callback function.
	 */
Binds the callback function to be executed the next time the channel is invoked, after which the
binding will be destroyed and the callback will no longer be invoked.

@param string $channel Event channel.
@param callable $callback Callback function.
Binds the callback function to be executed the next time the channel is invoked after which the binding will be destroyed and the callback will no longer be invoked . @param string $channel Event channel . @param callable $callback Callback function .
public function once($channel, callable $callback) {
		$this->prepare($channel);
		$this->hooks[$channel][] = new EventCallback($callback, EVENT_ONCE);
	}
public function once ( $ channel , callable $ callback ) { $ this -> prepare ( $ channel ) ; $ this -> hooks [ $ channel ] [ ] = new EventCallback ( $ callback , EVENT_ONCE ) ; }
Binds the callback function to be executed the next time the channel is invoked, after which the
 binding will be destroyed and the callback will no longer be invoked.
Binds the callback function to be executed the next time the channel is invoked after which the binding will be destroyed and the callback will no longer be invoked .
// Create an array for the channel if needed // Add the callback to the channel