Function gtk_source_sys::gtk_source_file_loader_load_async

pub unsafe extern "C" fn gtk_source_file_loader_load_async(
    loader: *mut GtkSourceFileLoader, 
    io_priority: c_int, 
    cancellable: *mut GCancellable, 
    progress_callback: GFileProgressCallback, 
    progress_callback_data: gpointer, 
    progress_callback_notify: GDestroyNotify, 
    callback: GAsyncReadyCallback, 
    user_data: gpointer
)