Add DEFINE_HANDLER_SIGNATURE macro (#6)
Add DEFINE_HANDLER_SIGNATURE macro (#6)

* Add DEFINE_HANDLER_SIGNATURE macro

googlecartographer/async_grpc,cartographer-project/async_grpc,cartographer-project/async_grpc,googlecartographer/async_grpc,googlecartographer/async_grpc,cartographer-project/async_grpc