NewRawSubscriptionHandler returns a RawSubscriptionHandler that invokes the given function when SubscriptionHandler.Notify is invoked.

NewSubscriptionHandler returns a SubscriptionHandler that invokes the given function when SubscriptionHandler.Notify is invoked.

NewTestGRPCServer is a utility function that spins up a TCP listener on a random local port along with a grpc.Server.

FuncHandler is a SubscriptionHandler implementation that simply invokes a function.

TestServer is instantiated with NewTestGRPCServer and serves to facilitate local testing against gRPC service implementations.