protected NavigableMap<K, V> delegate() {
      return (NavigableMap<K, V>) super.delegate();
    }

    @Override
    public @Nullable Entry<K, V> ceilingEntry(K key) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate().ceilingEntry(key);
    }

    @Override
    public @Nullable K ceilingKey(K key) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate().ceilingKey(key);

    this.delegate = checkNotNull(delegate);
    for (K k : keySet()) {
      checkValid(k);
    }
  }

  @Override
  public @Nullable Entry<K, V> ceilingEntry(K key) {
    return delegate.ceilingEntry(checkValid(key));
  }

  @Override
  public @Nullable K ceilingKey(K key) {
    return delegate.ceilingKey(checkValid(key));
  }

  @Override
  public void clear() {

    this.delegate = checkNotNull(delegate);
    for (K k : keySet()) {
      checkValid(k);
    }
  }

  @Override
  public @Nullable Entry<K, V> ceilingEntry(K key) {
    return delegate.ceilingEntry(checkValid(key));
  }

  @Override
  public @Nullable K ceilingKey(K key) {
    return delegate.ceilingKey(checkValid(key));
  }

  @Override
  public void clear() {

    }
  }

  @Override
  public boolean intersects(Range<C> range) {
    checkNotNull(range);
    Entry<Cut<C>, Range<C>> ceilingEntry = rangesByLowerBound.ceilingEntry(range.lowerBound);
    if (ceilingEntry != null
        && ceilingEntry.getValue().isConnected(range)
        && !ceilingEntry.getValue().intersection(range).isEmpty()) {
      return true;
    }

      return sortedMap().floorKey(key);
    }

    @Override
    public @Nullable Entry<K, Collection<V>> ceilingEntry(@ParametricNullness K key) {
      Entry<K, Collection<V>> entry = sortedMap().ceilingEntry(key);
      return (entry == null) ? null : wrapEntry(entry);
    }

    @Override
    public @Nullable K ceilingKey(@ParametricNullness K key) {

      return sortedMap().floorKey(key);
    }

    @Override
    public @Nullable Entry<K, Collection<V>> ceilingEntry(@ParametricNullness K key) {
      Entry<K, Collection<V>> entry = sortedMap().ceilingEntry(key);
      return (entry == null) ? null : wrapEntry(entry);
    }

    @Override
    public @Nullable K ceilingKey(@ParametricNullness K key) {

    return keyOrNull(floorEntry(key));
  }

  @Override
  public @Nullable Entry<K, V> ceilingEntry(K key) {
    return tailMap(key, true).firstEntry();
  }

  @Override
  public @Nullable K ceilingKey(K key) {
    return keyOrNull(ceilingEntry(key));
  }

  @Override
  public @Nullable Entry<K, V> higherEntry(K key) {
    return tailMap(key, false).firstEntry();

    NavigableMap<K, V> delegate() {
      return (NavigableMap<K, V>) super.delegate();
    }

    @Override
    public Map.@Nullable Entry<K, V> ceilingEntry(K key) {
      synchronized (mutex) {
        return nullableSynchronizedEntry(delegate().ceilingEntry(key), mutex);
      }
    }

    @Override
    public @Nullable K ceilingKey(K key) {
      synchronized (mutex) {

    NavigableMap<K, V> delegate() {
      return (NavigableMap<K, V>) super.delegate();
    }

    @Override
    public Map.@Nullable Entry<K, V> ceilingEntry(K key) {
      synchronized (mutex) {
        return nullableSynchronizedEntry(delegate().ceilingEntry(key), mutex);
      }
    }

    @Override
    public @Nullable K ceilingKey(K key) {
      synchronized (mutex) {

      super(fromMap, transformer);
    }

    @Override
    public @Nullable Entry<K, V2> ceilingEntry(@ParametricNullness K key) {
      return transformEntry(fromMap().ceilingEntry(key));
    }

    @Override
    public @Nullable K ceilingKey(@ParametricNullness K key) {
      return fromMap().ceilingKey(key);
    }

    @Override