private synchronized void evict() {
    this.evictBasedOnSize();
    this.evictBasedOnTimestamp();
  }
Evicts entries from the elements list, based on the given item-size and durationThreshold.
Concurrent eviction threads can cause incorrectness (when reading elements.size or elements.peek).
samza-core/src/main/scala/org/apache/samza/diagnostics/BoundedList.java