Function gio_sys::g_volume_eject_with_operation

pub unsafe extern fn g_volume_eject_with_operation(volume: *mut GVolume,
                                                   flags: GMountUnmountFlags,
                                                   mount_operation: *mut GMountOperation,
                                                   cancellable: *mut GCancellable,
                                                   callback: GAsyncReadyCallback,
                                                   user_data: gpointer)