Asynchronously prompt a user for a decision on an extension-provided dialog.
The caller usually provides an extension for UserPrompterServer, a descendant of
UserPrompterServerExtension, which registers itself as a dialog
provider. The extension defines dialog_name, same as meaning of in_parameters; only the extension and the caller
know about meaning of these.
When the operation is finished, callback will be called. You can then call extension_prompt.end
to get the result of the operation. If there is no extension providing given dialog name, the operation finishes with a G_IO_ERROR,
G_IO_ERROR_NOT_FOUND Error.
| this |
an UserPrompter |
| dialog_name |
name of a dialog to invoke |
| in_parameters |
optional parameters to pass to extension; can be null |
| cancellable |
optional Cancellable object, or null |
| callback |
a TaskReadyCallback to call when the request is satisfied |
| user_data |
data to pass to the callback function |