How to know when I can send a new event

[Marco Trapanese]

I periodically send a step event in this way:

QGst::StepEventPtr evt = QGst::StepEvent::create(QGst::FormatBuffers, 1, 
1.0, TRUE, FALSE);
m_pipeline->sendEvent(evt);

When I call this piece of code too fast the video hangs. I guess it's 
because I request a new event before the previous has been completed.

How to know that so I don't send the next one?
Thanks!
Marco