Allow to remove listeners

lib/private/EventDispatcher/EventDispatcher.php

@@ -63,6 +63,11 @@ public function addListener(string $eventName,
 		$this->dispatcher->addListener($eventName, $listener, $priority);
 	}
 
+	public function removeListener(string $eventName,
+								   callable $listener): void {
+		$this->dispatcher->removeListener($eventName, $listener);
+	}
+
 	public function addServiceListener(string $eventName,
 									   string $className,
 									   int $priority = 0): void {

lib/public/EventDispatcher/IEventDispatcher.php

@@ -42,6 +42,14 @@ interface IEventDispatcher {
 	 */
 	public function addListener(string $eventName, callable $listener, int $priority = 0): void;
 
+	/**
+	 * @param string $eventName preferably the fully-qualified class name of the Event sub class
+	 * @param callable $listener the object that is invoked when a matching event is dispatched
+	 *
+	 * @since 19.0.0
+	 */
+	public function removeListener(string $eventName, callable $listener): void;
+
 	/**
 	 * @param string $eventName preferably the fully-qualified class name of the Event sub class to listen for
 	 * @param string $className fully qualified class name (or ::class notation) of a \OCP\EventDispatcher\IEventListener that can be built by the DI container