Init initializes global root metrics scope instance, all callers can only use it to extend sub scope.

NewOpts create metrics options based config file.

Shutdown closes underlying resources used by metrics server.

Start starts metrics server.

Counter is the interface for emitting Counter type metrics.

Gauge is the interface for emitting Gauge metrics.

Scope is a namespace wrapper around a stats Reporter, ensuring that all emitted values have a given prefix or set of tags.