Callbacks are called when the data buffer of the message assiciated
with the corresponding region is no longer needed by the transport.
Example in examples/advanced/Region/
- give transport Initialize() method with access to device config.
- avoid using global context in the transport.
- simplify shutdown procedure (no need for extra thread).
- Avoid polling when only one input channel is used.
- Send only handles for shared memory transport.
- Avoid waiting in the rate logger thread when nothing to log.
- Hide warnings from generated files
- Fix#483
