RequestHandler typedef
HTTP request handler function type.
Methods of this type are used as the handler that is invoked when a rule's pattern matches the request.
If the future returns a response, processing stops and that response is used to produce the HTTP response. If the future returns null, the search continues for another matching rule.
Used for in the rules of a ServerPipeline.
Note: this will be changed to return a Future
Implementation
typedef RequestHandler = Future<Response?> Function(Request req);