* Move the handling of GST_EVENT_STREAM_START on a slot to a separate function * There was a lot of usage of `gst_stream_get_stream_id()` for the slot active_stream. Cache that instead of constantly querying it. * Rename the variables in `handle_stream_switch()` to be clearer Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/6774>