func (c *LRU[K, V]) Contains(key K) (ok bool) {
	c.mu.RLock()
	defer c.mu.RUnlock()
	_, ok = c.items[key]
	return ok
}

// Peek returns the key value (or undefined if not found) without updating
// the "recently used"-ness of the key.
func (c *LRU[K, V]) Peek(key K) (value V, ok bool) {
	c.mu.RLock()
	defer c.mu.RUnlock()
	var ent *Entry[K, V]
	if ent, ok = c.items[key]; ok {
		// Expired item check

 *
 * <ul>
 *   <li>for an unnested {@code lock()} and {@code unlock()}, a cycle detecting lock takes 38ns as
 *       opposed to the 24ns taken by a plain lock.
 *   <li>for nested locking, the cost increases with the depth of the nesting:
 *       <ul>
 *         <li>2 levels: average of 64ns per lock()/unlock()
 *         <li>3 levels: average of 77ns per lock()/unlock()
 *         <li>4 levels: average of 99ns per lock()/unlock()

            // Then - if we get here without exception, the unlock/lock worked
            DfFinalTimeZoneProvider provider = getDBFluteSystemTimeZoneProvider();
            // Provider might be null due to reflection limitations, which is ok
            assertTrue("processDBFluteSystem executed without exception", true);
        } catch (Exception e) {
            fail("processDBFluteSystem should handle unlock/lock properly: " + e.getMessage());
        }

 *       return result;
 *     } finally {
 *       lock.unlock();
 *     }
 *   }
 *
 *   public void set(V newValue) throws InterruptedException {
 *     lock.lock();
 *     try {
 *       while (value != null) {
 *         valueAbsent.await();
 *       }
 *       value = newValue;
 *       valuePresent.signal();
 *     } finally {
 *       lock.unlock();
 *     }
 *   }
 * }
 * }
 *

      try {
        condition.await();
      } finally {
        lock.unlock();
      }
    }

    @Override
    public boolean await(long time, TimeUnit unit) throws InterruptedException {
      lock.lock();
      try {
        return condition.await(time, unit);
      } finally {
        lock.unlock();
      }
    }

    @Override
    public void awaitUninterruptibly() {

      } finally {
        unlock();
        postWriteCleanup();
      }
    }

    // reference queues, for garbage collection cleanup

    /** Cleanup collected entries when the lock is available. */
    void tryDrainReferenceQueues() {
      if (tryLock()) {
        try {
          drainReferenceQueues();
        } finally {
          unlock();
        }
      }
    }

      } finally {
        unlock();
        postWriteCleanup();
      }
    }

    // reference queues, for garbage collection cleanup

    /** Cleanup collected entries when the lock is available. */
    void tryDrainReferenceQueues() {
      if (tryLock()) {
        try {
          drainReferenceQueues();
        } finally {
          unlock();
        }
      }
    }

    /** Cleanup collected entries when the lock is available. */
    void tryDrainReferenceQueues() {
      if (tryLock()) {
        try {
          maybeDrainReferenceQueues();
        } finally {
          unlock();
        }
      }
    }

    @GuardedBy("this")
    void drainKeyReferenceQueue(ReferenceQueue<K> keyReferenceQueue) {
      Reference<? extends K> ref;
      int i = 0;

    public void blockIp(final String ip, final long durationMs) {
        blockedIps.put(ip, Boolean.TRUE);
        logger.info("IP manually blocked: ip={}", ip);
    }

    /**
     * Unblock an IP address.
     * @param ip the IP address to unblock
     */
    public void unblockIp(final String ip) {
        blockedIps.invalidate(ip);
        logger.info("IP unblocked: ip={}", ip);
    }

    /**

    GcFinalization.awaitClear(garbage);
    Lock writeLock = striped.get(key).writeLock();
    readLock.lock();
    try {
      assertFalse(writeLock.tryLock());
    } finally {
      readLock.unlock();
    }
  }

  private WeakReference<Object> createGarbage() {
    return new WeakReference<>(new Object());
  }

  public void testStrongImplementations() {