DBusInterfaceInfo.cacheBuild

Builds a lookup-cache to speed up [gio.dbus_interface_info.DBusInterfaceInfo.lookupMethod], [gio.dbus_interface_info.DBusInterfaceInfo.lookupSignal] and [gio.dbus_interface_info.DBusInterfaceInfo.lookupProperty].

If this has already been called with info, the existing cache is used and its use count is increased.

Note that info cannot be modified until [gio.dbus_interface_info.DBusInterfaceInfo.cacheRelease] is called.