public void addConfig(Config config) {
    addToMetricsMessage(GROUP_NAME_FOR_DIAGNOSTICS_MANAGER, CONFIG_METRIC_NAME, (Map<String, String>) config);
  }
Add the job's config to the message.
@param config the config to add.
samza-core/src/main/scala/org/apache/samza/diagnostics/DiagnosticsStreamMessage.java