Expose TypeHash and TypeDescription on generated types #200
Description
Feature request
Feature description
The C generated code for types exposes this info, we need to bridge it through the generated python types.
An initial aborted attempt was at #191
Related to ros2/ros2#1159
Implementation considerations
Access to the type_description_interfaces types at this stage. There is rosidl_runtime_c versions - maybe we move some implementation up to rclpy where the message types will be available?