Sets this into an error state.
This will pause the stream (you can check for an error via [[email protected]_error] in your GtkMediaStream.pause() implementation), abort pending seeks and mark the stream as prepared.
if the stream is already in an error state, this call will be ignored and the existing error will be retained.
To unset an error, the stream must be reset via a call to [[email protected]].
| this |
a `GtkMediaStream` |
| error |
the `GError` to set |