Method setAttribute

libminifi/include/core/FlowFile.h:158–160

* setAttribute, if attribute already there, update it, else, add it */

   * setAttribute, if attribute already there, update it, else, add it
   */
  bool setAttribute(const std::string& key, const std::string& value) {
    return attributes_.insert_or_assign(key, value).second;
  }

  /**
   * Returns the map of attributes