private void onOriginConnectSucceeded(PooledConnection conn, Duration readTimeout) {
        passport.add(PassportState.ORIGIN_CONN_ACQUIRE_END);

        if (context.isCancelled()) {
            logger.info("Client cancelled after successful origin connect: {}", conn.getChannel());

            // conn isn't actually busy so we can put it in the pool
            conn.setConnectionState(PooledConnection.ConnectionState.WRITE_READY);
            conn.release();
        } else {
            // Update the RequestAttempt to reflect the readTimeout chosen.
            currentRequestAttempt.setReadTimeout(readTimeout.toMillis());

            // Start sending the request to origin now.
            writeClientRequestToOrigin(conn, readTimeout);
        }
    }
Override to track your own request stats.
zuul-core/src/main/java/com/netflix/zuul/filters/endpoint/ProxyEndpoint.java