private MethodDescriptor<Message, Message> getCallMethod(final Object request) {
        final String interest = request.getClass().getName();
        final Message reqIns = Requires.requireNonNull(this.parserClasses.get(interest), "null default instance: "
                                                                                         + interest);
        return MethodDescriptor //
            .<Message, Message> newBuilder() //
            .setType(MethodDescriptor.MethodType.UNARY) //
            .setFullMethodName(MethodDescriptor.generateFullMethodName(interest, GrpcRaftRpcFactory.FIXED_METHOD_NAME)) //
            .setRequestMarshaller(ProtoUtils.marshaller(reqIns)) //
            .setResponseMarshaller(
                ProtoUtils.marshaller(this.marshallerRegistry.findResponseInstanceByRequest(interest))) //
            .build();
    }
GRPC RPC client implement.

@author nicholas.jxf
@author jiachun.fjc
jraft-extension/rpc-grpc-impl/src/main/java/com/alipay/sofa/jraft/rpc/impl/GrpcClient.java