Ultimately, the framework wants to track all grpc channels:

Send(context, method, input: proto.Message) (output: proto.Message, err)
Receive(context, method, input: proto.Message) (output: proto.Message, err)

Currently, we need to intercept because we need to sync the epoch. We use

DataRequest
CheckGRPCContext

to achieve that.
But I think CheckGRPCContext is not what we want.
A better alternative to current situation (before grpc supports it) is to ask all grpc server handler to send its messages to framework:

framework.GRPCReceive(context, method, input) (output, err)

and it will trigger the user callback Receive.