This bug affects:
https://bugs.php.net/bug.php?id=62976
public function testWorkaroundForPhpBug62976() {
$dispatcher = new EventDispatcher();
$dispatcher
->addListener('bug.62976', new CallableClass());
$dispatcher
->removeListener('bug.62976', function () {
});
$this
->assertTrue($dispatcher
->hasListeners('bug.62976'));
}