Function gio_sys::g_file_create_readwrite_async

pub unsafe extern fn g_file_create_readwrite_async(file: *mut GFile,
                                                   flags: GFileCreateFlags,
                                                   io_priority: c_int,
                                                   cancellable: *mut GCancellable,
                                                   callback: GAsyncReadyCallback,
                                                   user_data: gpointer)