class RemitSyncExecutor implements Handler.Callback {

    public void postRemoveFreeId(int id) {
        final Message message = handler.obtainMessage(WHAT_REMOVE_FREE_ID);
        message.arg1 = id;
        handler.sendMessage(message);
    }

      RemitSyncExecutor(@NonNull RemitAgent agent);
      RemitSyncExecutor(@NonNull RemitAgent agent, @Nullable Handler handler,
                      @NonNull Set<Integer> freeToDBIdList);

}