Start the input capture session.
When the request is done, callback will be called. You can then call [method@InputCaptureSession.start_finish] to get the
results.
| this |
a [class@XdpInputCaptureSession] |
| parent |
parent window information |
| capabilities |
which kinds of capabilities to request |
| cancellable |
optional [class@Gio.Cancellable] |
| callback |
a callback to call when the request is done |
| data |
data to pass to |