private void noteExpiredLease() {
    if (logger.isTraceEnabled(LogMarker.DLS_VERBOSE)) {
      logger.trace(LogMarker.DLS_VERBOSE, "[noteExpiredLease] {}", thread);
    }
    if (expiredLeases == null) {
      expiredLeases = new WeakHashMap();
    }
    expiredLeases.put(thread, null);
  }
Record the token's owning thread as having lost its lease, so it can throw an exception later
if it tries to unlock. A weak reference to the thread is used. Caller must synchronize on this
lock token.
geode-core/src/main/java/org/apache/geode/distributed/internal/locks/DLockToken.java