@Override
  protected void performTimeout() throws CacheException {
    // remove the task from the region's map first thing
    // so the next call to addExpiryTaskIfAbsent will
    // add a new task instead of doing nothing, which would
    // erroneously cancel expiration for this key.
    getLocalRegion().cancelExpiryTask(re, this);
    getLocalRegion().performExpiryTimeout(this);
  }
Returns the tasks region entry if it "checks" out. The check is to see if the region entry
still exists.

@throws EntryNotFoundException if the task no longer has a region entry or if the region entry
        it has is removed.
geode-core/src/main/java/org/apache/geode/internal/cache/EntryExpiryTask.java