message: docs: transocder route config
diff: @@ -35,3 +35,30 @@ Then run protoc to generate the descriptor set from bookstore.proto:
  --descriptor_set_out=proto.pb test/proto/bookstore.proto
  If you have more than one proto source files, you can pass all of them in one command.
  +
  +Route configs for transcoded requests
  +-------------------------------------
  +
  +The route configs to be used with the gRPC-JSON transcoder should be identical to the gRPC route.
  +The requests processed by the transcoder filter will have `/<package>.<service>/<method>` path and
  +`POST` method. The route configs for those requests should match on `/<package>.<service>/<method>`,
  +not the incoming request path. This allows the routes to be used for both gRPC requests and
  +gRPC-JSON transcoded requests.
  +
  +For example, with the following proto example, the router will process `/helloworld.Greeter/SayHello`
  +as the path, so the route config prefix `/say` won't match requests to `SayHello`. If you want to
  +match the incoming request path, set `match_incoming_request_route` to true.
  +
  +.. code-block:: proto
  +
  + package helloworld;
  +
  + // The greeting service definition.
  + service Greeter {
  + // Sends a greeting
  + rpc SayHello (HelloRequest) returns (HelloReply) {
  + option (google.api.http) = {
  + get: "/say"
  + };
  + }
  + }
  