@VisibleForTesting
  @Override
  public boolean isLocked() {
    // Best-effort check. We cannot do a good check against caller thread, since
    // refCount could still be > 0 if someone else locked. This is used for asserts and logs.
    return State.getRefCount(state.get()) > 0;
  }
Allocator uses this to remember the allocation size. Somewhat redundant with header.
llap-server/src/java/org/apache/hadoop/hive/llap/cache/LlapAllocatorBuffer.java