synchronized (mutex) {
        return delegate().put(key, value);
      }
    }

    @Override
    @CheckForNull
    public V putIfAbsent(K key, V value) {
      synchronized (mutex) {
        return delegate().putIfAbsent(key, value);
      }
    }

    @Override
    public boolean replace(K key, V oldValue, V newValue) {
      synchronized (mutex) {

    checkNotNull(value);
    int hash = hash(key);
    return segmentFor(hash).put(key, hash, value, false);
  }

  @CheckForNull
  @CanIgnoreReturnValue
  @Override
  public V putIfAbsent(K key, V value) {
    checkNotNull(key);
    checkNotNull(value);
    int hash = hash(key);
    return segmentFor(hash).put(key, hash, value, true);
  }

  @Override

    checkNotNull(value);
    int hash = hash(key);
    return segmentFor(hash).put(key, hash, value, false);
  }

  @CheckForNull
  @CanIgnoreReturnValue
  @Override
  public V putIfAbsent(K key, V value) {
    checkNotNull(key);
    checkNotNull(value);
    int hash = hash(key);
    return segmentFor(hash).put(key, hash, value, true);
  }

  @Override