Function shumate_data_source_get_tile_data_async

pub unsafe extern "C" fn shumate_data_source_get_tile_data_async(
    self_: *mut ShumateDataSource,
    x: c_int,
    y: c_int,
    zoom_level: c_int,
    cancellable: *mut GCancellable,
    callback: GAsyncReadyCallback,
    user_data: gpointer,
)