Initial interface rework to allow knowing whether to pull payload at registration, not at request time
diff --git a/include/grpc/impl/codegen/grpc_types.h b/include/grpc/impl/codegen/grpc_types.h
index b09b1cd..38da99b 100644
--- a/include/grpc/impl/codegen/grpc_types.h
+++ b/include/grpc/impl/codegen/grpc_types.h
@@ -185,7 +185,9 @@
       server */
   GRPC_CALL_ERROR_NOT_SERVER_COMPLETION_QUEUE,
   /** this batch of operations leads to more operations than allowed */
-  GRPC_CALL_ERROR_BATCH_TOO_BIG
+  GRPC_CALL_ERROR_BATCH_TOO_BIG,
+  /** payload type requested is not the type registered */
+  GRPC_CALL_ERROR_PAYLOAD_TYPE_MISMATCH
 } grpc_call_error;
 
 /* Write Flags: */