code: @Override
    public Long touch(final byte[]... keys) {
      checkIsInMultiOrPipeline();
      client.touch(keys);
      return client.getIntegerReply();
    }
docs: Alters the last access time of a key(s). A key is ignored if it does not exist.
  Time complexity: O(N) where N is the number of keys that will be touched.
  @param keys
  @return Integer reply: The number of keys that were touched.