@Override
    public ValueSetLink<K, V> getPredecessorInValueSet() {
      return requireNonNull(predecessorInValueSet); // see the comment on the class fields
    }

    @Override
    public ValueSetLink<K, V> getSuccessorInValueSet() {
      return requireNonNull(successorInValueSet); // see the comment on the class fields
    }

    @Override
    public void setPredecessorInValueSet(ValueSetLink<K, V> entry) {

  @GwtIncompatible // SerializableTester
  public void testIsEqualToNull_serialization() {
    checkSerialization(Predicates.equalTo(null));
  }

  /**
   * Tests for Predicates.instanceOf(x). TODO: Fix the comment style after fixing annotation
   * stripper to remove comments properly. Currently, all tests before the comments are removed as
   * well.
   */
  @GwtIncompatible // Predicates.instanceOf

     * is to avoid unnecessary stalls in situations like this: A RateLimiter of 1qps, and 4 threads,
     * all calling acquire() at these moments:
     *
     * T0 at 0 seconds
     * T1 at 1.05 seconds
     * T2 at 2 seconds
     * T3 at 3 seconds
     *
     * Due to the slight delay of T1, T2 would have to sleep till 2.05 seconds, and T3 would also

      this.right = null;
    }

    /** Constructor for the header node. */
    AvlNode() {
      this.elem = null;
      this.elemCount = 1;
    }

    // For discussion of pred() and succ(), see the comment on the pred and succ fields.

    private AvlNode<E> pred() {
      return requireNonNull(pred);
    }

    private AvlNode<E> succ() {
      return requireNonNull(succ);
    }

   */
  @CanIgnoreReturnValue
  public static int checkElementIndex(int index, int size, String desc) {
    // Carefully optimized for execution by hotspot (explanatory comment above)
    if (index < 0 || index >= size) {
      throw new IndexOutOfBoundsException(badElementIndex(index, size, desc));
    }
    return index;
  }

       */
      KeyList<K, V> keyList = requireNonNull(keyToKeyList.remove(node.key));
      keyList.count = 0;
      modCount++;
    } else {
      // requireNonNull is safe (under the conditions listed in the comment in the branch above).
      KeyList<K, V> keyList = requireNonNull(keyToKeyList.get(node.key));
      keyList.count--;

      if (node.previousSibling == null) {

    checkState(count() > 1);
    return sumOfProductsOfDeltas / (count() - 1);
  }

  /**
   * Returns the <a href="http://mathworld.wolfram.com/CorrelationCoefficient.html">Pearson's or
   * product-moment correlation coefficient</a> of the values. The count must greater than one, and
   * the {@code x} and {@code y} values must both have non-zero population variance (i.e. {@code

    tester.testStaticMethods(PatternFilenameFilter.class, Visibility.PACKAGE); // currently none

    // The reason that we skip this method is discussed in a comment on the method.
    tester.ignore(PatternFilenameFilter.class.getMethod("accept", File.class, String.class));
    tester.testInstanceMethods(new PatternFilenameFilter(".*"), Visibility.PACKAGE);
  }

   * unsupported type/method. E.g. "Class.isInstance".
   *
   * <p>As of Guava 20.0, this value is optional. We encourage authors who wish to describe why an
   * API is {@code @GwtIncompatible} to instead leave an implementation comment.
   */
  String value() default "";

    void forceJdk() {
      requireNonNull(impl); // see the comment on the field
      this.impl = new JdkBackedSetBuilderImpl<>(impl);
    }

    final void copyIfNecessary() {
      if (forceCopy) {
        copy();
        forceCopy = false;
      }
    }

    void copy() {
      requireNonNull(impl); // see the comment on the field
      impl = impl.copy();
    }

    @Override