Not all the service requests require a response. We'd add some logic for removing the service request handler after sending the request, instead of waiting for the response. We could use the msgs::Empty for not having to modify the wire format when sending a service request. We'd create a new Request function in the Node class with only one parameter (the input parameter).
Two examples are included SrvProviderOneway and RequesterOneway.
Amitoj Hanspal, could you create a separate pull request for documenting your changes in the tutorials? It should go in the "Using services" section of the documentation. Please, target the new pull request to ign-transport2 branch.
Also, do you mind answering all comments to make sure that all the feedback has been addressed? Ideally, with the commit that solves the suggestion. It's a little bit of extra work but much more convenient for the reviewers.
The new examples don't compile. See my suggestions below. For the future, make sure that the library and all examples compile, all tests pass and the new examples work before submitting the pull request. I know there are lots of things to check but you'll catch all the problems faster :)