int getPersistedEntrySize() {
    rwLock.readLock().lock();
    int sz = sealed.get() ? sealedIndex.getPersistedEntrySize() : maxEntrySize;
    rwLock.readLock().unlock();
    return sz;
  }
@return The entry size of this segment
It's for testing purpose only.
ambry-store/src/main/java/com/github/ambry/store/IndexSegment.java