private void incrementStateCounter(PassportState state) {
        switch (state) {
            case IN_REQ_HEADERS_RECEIVED:
                IN_REQ_HEADERS_RECEIVED_CNT.increment();
                break;
            case IN_REQ_LAST_CONTENT_RECEIVED:
                IN_REQ_LAST_CONTENT_RECEIVED_CNT.increment();
                break;
            case OUT_REQ_HEADERS_SENT:
                OUT_REQ_HEADERS_SENT_CNT.increment();
                break;
            case OUT_REQ_LAST_CONTENT_SENT:
                OUT_REQ_LAST_CONTENT_SENT_CNT.increment();
                break;
            case IN_RESP_HEADERS_RECEIVED:
                IN_RESP_HEADERS_RECEIVED_CNT.increment();
                break;
            case IN_RESP_LAST_CONTENT_RECEIVED:
                IN_RESP_LAST_CONTENT_RECEIVED_CNT.increment();
                break;
            case OUT_RESP_HEADERS_SENT:
                OUT_RESP_HEADERS_SENT_CNT.increment();
                break;
            case OUT_RESP_LAST_CONTENT_SENT:
                OUT_RESP_LAST_CONTENT_SENT_CNT.increment();
                break;
            default:
                logger.debug("Not incrementing any state counter for state {}", state);
                break;
        }
    }
NOTE: This is NOT nanos since epoch. It's just since an arbitrary point in time. So only use relatively.
zuul-core/src/main/java/com/netflix/zuul/passport/CurrentPassport.java