InstrumentQueryDataHandler wraps a backend.QueryDataHandler with instrumentation of success rate and latency.

InstrumentQueryDataRequest instruments success rate and latency of query data request.

InstrumentTransformDataRequest instruments success rate and latency of transform data request.

ErrHealthCheckFailed error returned when health check failed.

ErrMethodNotImplemented error returned when plugin method not implemented.

ErrPluginNotRegistered error returned when plugin not registered.

ErrPluginUnavailable error returned when plugin is unavailable.

CallResourceClientResponseStream is used for receiving resource call responses.

Manager manages backend plugins.

Plugin backend plugin interface.

PluginFactoryFunc factory for creating a Plugin.