Use Empty rather than Any for message processing (#62)

Co-authored-by: Adam Sax <[email protected]>

Author: adamthesax

proxy/handler.go

@@ -10,7 +10,7 @@ import (
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
-	"google.golang.org/protobuf/types/known/anypb"
+	"google.golang.org/protobuf/types/known/emptypb"
 )
 
 var (
@@ -53,7 +53,7 @@ type handler struct {
 }
 
 // handler is where the real magic of proxying happens.
-// It is invoked like any gRPC server stream and uses the anypb.Any type server
+// It is invoked like any gRPC server stream and uses the emptypb.Empty type server
 // to proxy calls between the input and output streams.
 func (s *handler) handler(srv interface{}, serverStream grpc.ServerStream) error {
 	// little bit of gRPC internals never hurt anyone
@@ -112,7 +112,7 @@ func (s *handler) handler(srv interface{}, serverStream grpc.ServerStream) error
 func (s *handler) forwardClientToServer(src grpc.ClientStream, dst grpc.ServerStream) chan error {
 	ret := make(chan error, 1)
 	go func() {
-		f := &anypb.Any{}
+		f := &emptypb.Empty{}
 		for i := 0; ; i++ {
 			if err := src.RecvMsg(f); err != nil {
 				ret <- err // this can be io.EOF which is happy case
@@ -144,7 +144,7 @@ func (s *handler) forwardClientToServer(src grpc.ClientStream, dst grpc.ServerSt
 func (s *handler) forwardServerToClient(src grpc.ServerStream, dst grpc.ClientStream) chan error {
 	ret := make(chan error, 1)
 	go func() {
-		f := &anypb.Any{}
+		f := &emptypb.Empty{}
 		for i := 0; ; i++ {
 			if err := src.RecvMsg(f); err != nil {
 				ret <- err // this can be io.EOF which is happy case