@Override
    public void remove() {
      checkState(current != null, "no calls to next() since the last call to remove()");
      if (current != next) { // after call to next()
        previous = current.previousSibling;
        nextIndex--;
      } else { // after call to previous()
        next = current.nextSibling;
      }
      removeNode(current);
      current = null;
    }

    @Override

          double z = aa.getAndAdd(i, y);
          assertBitEquals(x, z);
          assertBitEquals(x + y, aa.get(i));
        }
      }
    }
  }

  /** addAndGet adds given value to current, and returns current value */
  public void testAddAndGet() {
    AtomicDoubleArray aa = new AtomicDoubleArray(SIZE);
    for (int i : new int[] {0, SIZE - 1}) {
      for (double x : VALUES) {
        for (double y : VALUES) {

      for (AvlNode<E> current = header.succ(); current != header; ) {
        AvlNode<E> next = current.succ();

        current.elemCount = 0;
        // Also clear these fields so that one deleted Entry doesn't retain all elements.
        current.left = null;
        current.right = null;
        current.pred = null;
        current.succ = null;

        current = next;
      }

      if (ownerType != null && JavaVersion.CURRENT.jdkTypeDuplicatesOwnerName()) {
        builder.append(JavaVersion.CURRENT.typeName(ownerType)).append('.');
      }
      return builder
          .append(rawType.getName())
          .append('<')
          .append(COMMA_JOINER.join(transform(argumentsList, JavaVersion.CURRENT::typeName)))
          .append('>')
          .toString();
    }

   */
  C offset(C origin, long distance) {
    C current = origin;
    checkNonnegative(distance, "distance");
    for (long i = 0; i < distance; i++) {
      current = next(current);
      if (current == null) {
        throw new IllegalArgumentException(
            "overflowed computing offset(" + origin + ", " + distance + ")");
      }
    }
    return current;
  }

  /**

   * @param timeoutUnit with timeoutDuration, the maximum length of time to wait
   * @return the result returned by the Callable
   * @throws TimeoutException if the time limit is reached
   * @throws InterruptedException if the current thread was interrupted during execution
   * @throws ExecutionException if {@code callable} throws a checked exception
   * @throws UncheckedExecutionException if {@code callable} throws a {@code RuntimeException}

  }

  /**
   * Returns whether the current thread is occupying this monitor (has entered more times than it
   * has left).
   */
  public boolean isOccupiedByCurrentThread() {
    return lock.isHeldByCurrentThread();
  }

  /**
   * Returns the number of times the current thread has entered this monitor in excess of the number
   * of times it has left. Returns 0 if the current thread is not occupying this monitor.
   */

      return false;
    }

    Object target = thatIterator.next();
    E current = thisIterator.next();
    try {
      while (true) {
        int cmp = unsafeCompare(current, target);

        if (cmp < 0) {
          if (!thisIterator.hasNext()) {
            return false;
          }
          current = thisIterator.next();
        } else if (cmp == 0) {
          if (!thatIterator.hasNext()) {

        long result = current.skip(n);
        if (result > 0) {
          return result;
        }
        advance();
      }
    }
    return 0;
  }

  @Override
  public boolean ready() throws IOException {
    return (current != null) && current.ready();
  }

  @Override
  public void close() throws IOException {
    if (current != null) {
      try {
        current.close();

          double z = aa.getAndAdd(i, y);
          assertBitEquals(x, z);
          assertBitEquals(x + y, aa.get(i));
        }
      }
    }
  }

  /** addAndGet adds given value to current, and returns current value */
  public void testAddAndGet() {
    AtomicDoubleArray aa = new AtomicDoubleArray(SIZE);
    for (int i : new int[] {0, SIZE - 1}) {
      for (double x : VALUES) {
        for (double y : VALUES) {