message: Only forward metric log to logstash
  Only forward metric log to logstash, not log metrics to console.
diff: @@ -76,6 +76,12 @@ public class LoggingConfiguration {
  asyncLogstashAppender.start();
  context.getLogger("ROOT").addAppender(asyncLogstashAppender);
  +
  + // Only forward metric log to logstash
  + ch.qos.logback.classic.Logger logger = (ch.qos.logback.classic.Logger) context.getLogger("metrics");
  + logger.addAppender(asyncLogstashAppender);
  + logger.setLevel(Level.ALL);
  + logger.setAdditive(false);
  }
  /**
  