Overridden by subclasses to modify or respond to an incoming request.
Subclasses override this method to provide their specific handling of a request. A RequestController should either modify or respond to the request. For concrete subclasses of RequestController - like HTTPController - this method has already been implemented.
RequestControllers should return a Response from this method if they responded to the request. If a RequestController does not respond to the request, but instead modifies it, this method must return the same Request.
Source
Future<RequestOrResponse> processRequest(Request req) { if (_listener != null) { return _listener(req); } return new Future.microtask(() => req); }