public static extern af_err af_set_default_random_engine_type(af_random_engine_type rtype);
public static extern af_err af_random_engine_set_type(out IntPtr engine, af_random_engine_type rtype);
public static extern af_err af_random_engine_get_type(out af_random_engine_type rtype, IntPtr engine);
public static extern af_err af_create_random_engine(out IntPtr engine, af_random_engine_type rtype, ulong seed);