InitializeClusterClientCollectors registers the cluster client metrics to the prometheus register and initializes them to 0 for all possible label combinations.

InitializeClusterServerCollectors registers the cluster server metrics to the prometheus register and initializes them to 0 for all possible label combinations.

InitializeHttpCollectors registers the proxy collectors to the provided prometheus register and initializes them to 0 for the most likely label combinations.

InitializeWebsocketCollectors registers the websocket collectors onto `r`.

InstrumentClusterClient wraps a UnaryClientInterceptor and records observations for the collectors associated with gRPC connections between the cluster and its clients.

InstrumentClusterStatsHandler returns a gRPC stats.Handler which observes cluster-specific metrics for a gRPC server.

InstrumentHttpHandler provides a handler which measures time until header is written by the server and attaches status code, method, and path labels for the relevant measurements.

InstrumentWebsocketWrapper expects an http.Handler where websockets are used and wraps it to instrument that websocket with metrics (bytes received, sent, etc).