type Config interface {
	RequestTimeout() time.Duration
	OperationTimeout() time.Duration
	OperationCancelAfter() time.Duration
	Meta(ctx context.Context) (context.Context, error)
	Trace(ctx context.Context) trace.Driver
	Pessimize(ctx context.Context, endpoint endpoint.Endpoint) error
	StreamTimeout() time.Duration
	GrpcConnectionPolicy() config.GrpcConnectionPolicy
}

type Conn interface {
	grpc.ClientConnInterface

	Endpoint() endpoint.Endpoint
	GetState() state.State
	SetState(context.Context, state.State) state.State
	Close(ctx context.Context) error
}