Dispatches operation requests.
__invoke( ICanBoogie\HTTP\Request $request )
Tries to create an ICanBoogie\Operation instance from the specified request. The
operation is then executed and its response returned.
If an operation could be created from the request, the operation
property of the request's context is set to that operation.
For forwarded operation, successful responses are not returned unless the
request is an XHR or the response has a location.
rescue( Exception $exception, ICanBoogie\HTTP\Request $request )
Fires ICanBoogie\Operation\RescueEvent and returns the response
provided by third parties. If no response was provided, the exception (or the
exception provided by third parties) is rethrown.