HashEntry<K, V> nextEntry() {
      if (nextEntry == null) {
        throw new NoSuchElementException();
      }
      lastReturned = nextEntry;
      advance();
      return lastReturned;
    }
Copy the tail of list of current matched entry ({@link #nextEntry}) to a temporary list, so
that the read lock can be released after the copy.

Read lock on {@link #currentSegmentIndex}'s listUpdateLock should already be acquired.
geode-core/src/main/java/org/apache/geode/internal/util/concurrent/CustomEntryConcurrentHashMap.java