MediaPlayer.playbackRate has no effect on Gstreamer/Linux

The playbackRate property seems to have no effect on the actual playback rate of media played by MediaPlayer.

I do see use of the property within the qgst_p.h and qgstreamermediaplayer.cpp files, and at a cursory glance, they seem to follow the process outlined in:

https://gstreamer.freedesktop.org/documentation/tutorials/basic/playback-speed.html?gi-language=c

... though no changes are observed. I do note that in the following page, it mentions that not all playback services support playbackRate, so maybe this is an expected or known limitation.

https://doc.qt.io/qt-5/qmediaplayer.html#playbackRate-prop