Element.callAsync

Calls func from another thread and passes user_data to it. This is to be used for cases when a state change has to be performed from a streaming thread, directly via [gst.element.Element.setState] or indirectly e.g. via SEEK events.

Calling those functions directly from the streaming thread will cause deadlocks in many situations, as they might involve waiting for the streaming thread to shut down from this very streaming thread.

MT safe.