Creates an inactive session for input capture.
When the request is done, callback will be called. You can then call [method@Portal.create_input_capture_session2_finish] to
get the results.
| this |
a [class@Portal] |
| cancellable |
optional [class@Gio.Cancellable] |
| callback |
a callback to call when the request is done |
| data |
data to pass to |