Representation of a server node that is part of a cluster, including
read-only accessors to state.
Whether server node is disabled: usually occurs during shutdowns
and startups, and is considered a transient state. Clients typically
try to avoid GET access from disabled nodes; and schedule updates
(if any) after all enabled instances.
Timestamp when last node state access request was sent.
Timestamp when last node state access response was received (note:
does NOT include cases where error occured during request).
Timestamp when last node state response update was processed.
Timestamp of the last update that has been fetched from the server node.
Timestamp of the latest update for the server node.
Accessor for getting path builder initialized to the root path of
the service for this node; used for building paths to access
things like entries and node state.