Codegen GRXWriter* instead of id<GRXWriter>
diff --git a/src/compiler/objective_c_generator.cc b/src/compiler/objective_c_generator.cc
index 2a74a3b..711d0d5 100644
--- a/src/compiler/objective_c_generator.cc
+++ b/src/compiler/objective_c_generator.cc
@@ -67,7 +67,7 @@
 
   printer->Print(vars, "- ($return_type$)$method_name$With");
   if (method->client_streaming()) {
-    printer->Print("RequestsWriter:(id<GRXWriter>)requestWriter");
+    printer->Print("RequestsWriter:(GRXWriter *)requestWriter");
   } else {
     printer->Print(vars, "Request:($request_class$ *)request");
   }