NewGRPCConnector creates a new GRPCConnector.

GRPCConnector establishes GRPC connections to dopplers and allows calls to Firehose, Stream, etc to be reduced down to a single Receiver.

DopplerPool creates a pool of doppler gRPC connections.

Finder yields events that tell us what dopplers are available.

MetricClient creates new CounterMetrics to be emitted periodically.