Add another missing return after a callback

src/node/src/client.js

@@ -117,6 +117,7 @@ function _write(chunk, encoding, callback) {
        programmer a useful error and to stop the stream properly */
     this.call.cancelWithStatus(grpc.status.INTERNAL, 'Serialization failure');
     callback(e);
+    return;
   }
   if (_.isFinite(encoding)) {
     /* Attach the encoding if it is a finite number. This is the closest we