time.c:903
static VALUE
time_to_s(time)
    VALUE time;
{
    struct time_object *tobj;
    char buf[128];
    int len;

    GetTimeval(time, tobj);
    if (tobj->tm_got == 0) {
	time_get_tm(time, tobj->gmt);
    }
    if (tobj->gmt == 1) {
	len = strftime(buf, 128, "%a %b %d %H:%M:%S UTC %Y", &tobj->tm);
    }
    else {
	len = strftime(buf, 128, "%a %b %d %H:%M:%S %Z %Y", &tobj->tm);
    }
    return rb_str_new(buf, len);
}
