+ expose the export transition in the session item class
+ make the export-related flags immutable
+ add an export error flag
+ update and improve documentation
+ replace calling execute_step(..., STEP_ERROR) with rollback
+ implement deactivate internally using rollback
This unifies deactivation steps, which are common between deactivate()
and calling execute_step() with WP_TRANSITION_STEP_ERROR at the
end of a failed activation transition.
* It should be possible to activate/deactivate while an item
is exported (if the item supports it, but that's a subclass matter)
* It should be possible to deactivate without resetting configuration
* introduces API to export session items
* introduces small changes in the WpSiEndpoint & WpSiStream
interfaces to make it nicer to work with
* ports WpImplEndpoint to use PW_TYPE_INTERFACE_Endpoint
to export. Depends on:
https://gitlab.freedesktop.org/pipewire/pipewire/-/merge_requests/246
(was merged after 0.3.2)
