private MethodDescriptor<Request, Response> getMethodDescriptor(SofaRequest sofaRequest) {
        String serviceName = sofaRequest.getInterfaceName();
        String methodName = sofaRequest.getMethodName();
        MethodDescriptor.Marshaller<?> requestMarshaller = ProtoUtils.marshaller(Request.getDefaultInstance());
        MethodDescriptor.Marshaller<?> responseMarshaller = ProtoUtils.marshaller(Response.getDefaultInstance());
        String fullMethodName = generateFullMethodName(serviceName, methodName);

        MethodDescriptor.Builder builder = MethodDescriptor
                .newBuilder()
                .setFullMethodName(fullMethodName)
                .setSampledToLocalTracing(true)
                .setRequestMarshaller((MethodDescriptor.Marshaller<Object>) requestMarshaller)
                .setResponseMarshaller((MethodDescriptor.Marshaller<Object>) responseMarshaller);

        String streamType = methodCallType.get(sofaRequest.getMethod().getName());
        MethodDescriptor.MethodType callType = SofaProtoUtils.mapGrpcCallType(streamType);
        builder.setType(callType);
        return builder.build();
    }
Build arg sigs for stream calls.

@param requestArgs request args
@return arg sigs, arg.getClass().getName().
remoting/remoting-triple/src/main/java/com/alipay/sofa/rpc/transport/triple/TripleClientInvoker.java