diff --git a/src/core/transport/transport.h b/src/core/transport/transport.h
index 5036dfc..7c4bed1 100644
--- a/src/core/transport/transport.h
+++ b/src/core/transport/transport.h
@@ -75,6 +75,7 @@
   grpc_pollset *bind_pollset;
 
   grpc_status_code cancel_with_status;
+  grpc_mdstr *cancel_message;
 } grpc_transport_op;
 
 /* Callbacks made from the transport to the upper layers of grpc. */
@@ -134,6 +135,8 @@
 
 void grpc_transport_op_finish_with_failure(grpc_transport_op *op);
 
+void grpc_transport_op_add_cancellation(grpc_transport_op *op, grpc_status_code status, grpc_mdstr *message);
+
 /* TODO(ctiller): remove this */
 void grpc_transport_add_to_pollset(grpc_transport *transport,
                                    grpc_pollset *pollset);