Method doAttach

api/src/test/java/io/grpc/ContextTest.java:903–906

(Context toAttach)

    try {
      storage.set(null, new Context.Storage() {
        @Override
        public Context doAttach(Context toAttach) {
          return null;
        }

        @Override
        public void detach(Context toDetach, Context toRestore) {