responder now checks routes added via add_route before mounted routes

routes added by `add_route` (including @api.route()) are now checked
before routes that were added by api.mount()

this especially helps cases for situations where the static route
defined by the API class is '/' but the default route is '/' as well

responder/routes.py

@@ -302,6 +302,15 @@ class Router:
         path = scope["path"]
         root_path = scope.get("root_path", "")
 
+        # Check "primary" mounted routes first (before submounted apps)
+        route = self._resolve_route(scope)
+
+        scope["before_requests"] = self.before_requests
+
+        if route is not None:
+            await route(scope, receive, send)
+            return
+
         # Call into a submounted app, if one exists.
         for path_prefix, app in self.apps.items():
             if path.startswith(path_prefix):
@@ -315,12 +324,4 @@ class Router:
                     await app(scope, receive, send)
                     return
 
-        route = self._resolve_route(scope)
-
-        scope["before_requests"] = self.before_requests
-
-        if route is not None:
-            await route(scope, receive, send)
-            return
-
         await self.default_response(scope, receive, send)