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

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