implements TestMultimapGenerator<String, String, M> {

    @Override
    public String[] createKeyArray(int length) {
      return new String[length];
    }

    @Override
    public String[] createValueArray(int length) {
      return new String[length];
    }

    @Override
    public SampleElements<String> sampleKeys() {

    private static final NullWriter INSTANCE = new NullWriter();

    @Override
    public void write(int c) {}

    @Override
    public void write(char[] cbuf) {
      checkNotNull(cbuf);
    }

    @Override
    public void write(char[] cbuf, int off, int len) {
      checkPositionIndexes(off, off + len, cbuf.length);
    }

    @Override
    public void write(String str) {
      checkNotNull(str);

    private volatile boolean shutdown;

    @Override
    public void shutdown() {
      shutdown = true;
    }

    @Override
    public List<Runnable> shutdownNow() {
      shutdown();
      return ImmutableList.of();
    }

    @Override
    public boolean isShutdown() {
      return shutdown;
    }

    @Override
    public boolean isTerminated() {
      return shutdown;

          @Override
          public void onSuccess(@Nullable Object result) {}

          @Override
          public void onFailure(Throwable t) {}
        };
    addCallback(f, callback, directExecutor());
  }

  private static final class CountingSameThreadExecutor implements Executor {
    int runCount = 0;

    @Override
    public void execute(Runnable command) {

        }

        @Override
        public long getMid() {
            return 0;
        }

        @Override
        public void setMid(long mid) {
        }

        @Override
        public int getCommand() {
            return 0;
        }

        @Override
        public void setCommand(int command) {
        }

        @Override
        public void setUid(int uid) {

    this.mutex = mutex;
  }

  @Override
  protected Set<E> delegate() {
    return delegate;
  }

  @Override
  public String toString() {
    assertTrue(Thread.holdsLock(mutex));
    return super.toString();
  }

  @Override
  public boolean equals(@Nullable Object o) {
    assertTrue(Thread.holdsLock(mutex));
    return super.equals(o);
  }

  @Override
  public int hashCode() {

  protected ForwardingBlockingDeque() {}

  @Override
  protected abstract BlockingDeque<E> delegate();

  @Override
  public int remainingCapacity() {
    return delegate().remainingCapacity();
  }

  @Override
  public void putFirst(E e) throws InterruptedException {
    delegate().putFirst(e);
  }

  @Override
  public void putLast(E e) throws InterruptedException {

  }

  @Override
  public final E set(int index, E element) {
    throw new UnsupportedOperationException();
  }

  @Override
  public final void add(int index, E element) {
    throw new UnsupportedOperationException();
  }

  @Override
  public final E remove(int index) {
    throw new UnsupportedOperationException();
  }

  @Override

        int attributes;

        @Override
        public int getAttributes() {
            return attributes;
        }

        @Override
        public long getCreateTime() {
            return createTime;
        }

        @Override
        public long getLastWriteTime() {
            return lastWriteTime;
        }

        @Override
        public long getSize() {
            return 0L;

    }

    @Override
    public void clear() {
      original.clear();
    }

    @Override
    public Map<C, V> column(@ParametricNullness R columnKey) {
      return original.row(columnKey);
    }

    @Override
    public Set<R> columnKeySet() {
      return original.rowKeySet();
    }

    @Override
    public Map<R, Map<C, V>> columnMap() {