protected long getIdleTimeoutInMillis() {
    long idle = getIdleAttributes().getTimeout();
    if (idle > 0) {
      idle = normalizeToMillis(idle);
    }
    return idle;
  }
Return the absolute time when idle expiration occurs, or 0 if not used
geode-core/src/main/java/org/apache/geode/internal/cache/ExpiryTask.java