QAudioSink with gstreamer backend plays audio with big latency.

QAudioSink with gstreamer seems playing with big latency(about 1 sec).
I made sample to reproduce the issue.
When program runs QAudioSink starts in pull mode and Generator produces waveform on the fly in readData(). (Generator does not have any buffer not to produce any lag. )

QAudioSink and Generator is always running and Generator writes waveform to stream if "Generate tone" is checked otherwise writes 0 to stream(no sound).

On linux tone starts to play after 1 second from checkbox is checked.
On windows starts to play immediately.