title: How is Zookeeper zk_max_latency calculated?
body: <p>Hi I just took some stats off my zookeeper...</p>
  
  <p>As you can see zk_max_latency is quite high. But is that the maximum it ever reached or is it always the current value?</p>
  
  <pre><code>echo mntr | nc localhost 2181
  zk_version  3.4.13-2d71af4dbe22557fda74f9a9b4309b15a7487f03, built on 06/29/2018 04:05 GMT
  zk_avg_latency  0
  zk_max_latency  4738
  zk_min_latency  0
  zk_packets_received 2387852
  zk_packets_sent 2387928
  zk_num_alive_connections    29
  zk_outstanding_requests 0
  zk_server_state follower
  zk_znode_count  7973
  zk_watch_count  74
  zk_ephemerals_count 22
  zk_approximate_data_size    12356979
  zk_open_file_descriptor_count   62
  zk_max_file_descriptor_count    16384
  zk_fsync_threshold_exceed_count 2
  </code></pre>