`server` Metricset fetches the data returned by the `srvr` admin keyword.

* *connections*: Connections established by the server
* *latency.avg*: Average latency of the server
* *latency.max*: Max latency reached by the server
* *latency.min*: Minimum latency that has been reached by the server
* *mode*: Server mode
* *node_count*: Total number of nodes
* *outstanding*: Outstanding
* *received*: Received requests to the server
* *sent*: Requests sent by the server
* *version_date*: Date of the Zookeeper release in use
* *zxid*: Original value of the Zookeeper transaction ID
* *count*: Total transactions of the leader in epoch
* *epoch*: Epoch value of the Zookeeper transaction ID
