Serializes message to a blob. The byte order returned by gio.dbus_message.DBusMessage.getByteOrder will be used.
A #GDBusCapabilityFlags describing what protocol features are supported.
A pointer to a valid binary D-Bus message of out_size bytes generated by message or null if error is set. Free with glib.global.gfree.
Serializes message to a blob. The byte order returned by gio.dbus_message.DBusMessage.getByteOrder will be used.