private function popAndRunBusyCallback() {
		if ( $this->busyCallbacks ) {
			reset( $this->busyCallbacks );
			$key = key( $this->busyCallbacks );
			/** @var callable $workCallback */
			$workCallback =& $this->busyCallbacks[$key];
			try {
				$workCallback();
			} catch ( \Exception $e ) {
				$workCallback = function () use ( $e ) {
					throw $e;
				};
			}
			unset( $this->busyCallbacks[$key] ); // consume

			return true;
		}

		return false;
	}
private function popAndRunBusyCallback() {
		if ( $this->busyCallbacks ) {
			reset( $this->busyCallbacks );
			$key = key( $this->busyCallbacks );
			/** @var callable $workCallback */
			$workCallback =& $this->busyCallbacks[$key];
			try {
				$workCallback();
			} catch ( \Exception $e ) {
				$workCallback = function () use ( $e ) {
					throw $e;
				};
			}
			unset( $this->busyCallbacks[$key] ); // consume

			return true;
		}

		return false;
	}
private function popAndRunBusyCallback ( ) { if ( $ this -> busyCallbacks ) { reset ( $ this -> busyCallbacks ) ; $ key = key ( $ this -> busyCallbacks ) ; /** @var callable $workCallback */ $ workCallback = & $ this -> busyCallbacks [ $ key ] ; try { $ workCallback ( ) ; } catch ( \ Exception $ e ) { $ workCallback = function ( ) use ( $ e ) { throw $ e ; } ; } unset ( $ this -> busyCallbacks [ $ key ] ) ; // consume return true ; } return false ; }
Run one of the callbacks that does work ahead of time for another caller

@return bool Whether a callback was executed
Run one of the callbacks that does work ahead of time for another caller