`UnmodifiableMultimap.forEach` uses the `Multimap.forEach` default implementation which involves listing entries, and creating a new lambda instead of simply passing the BiConsumer through to the protected instance. This is safe to pass directly though because `forEach(BiConsumer)` is a read-only operation.
if (it.hasNext()) {
      T prev = it.next();
      while (it.hasNext()) {
        T next = it.next();
        if (compare(prev, next) >= 0) {
          return false;
        }
        prev = next;
      }
    }
    return true;
  }
  /**
   * {@link Collections#binarySearch(List, Object, Comparator) Searches} {@code sortedList} for
   * {@code key} using the binary search algorithm. The list must be sorted using this ordering.
   *
   * @param sortedList the list to be searched
   * @param key the key to be searched for
   * @deprecated Use {@link Collections#binarySearch(List, Object, Comparator)} directly.
   */
  @Deprecated
  public int binarySearch(List<? extends T> sortedList, @Nullable T key) {
    return Collections.binarySearch(sortedList, key, this);
  }
  /**
   * Exception thrown by a {@link Ordering#explicit(List)} or {@link Ordering#explicit(Object,
   * Object[])} comparator when comparing a value outside the set of values it can compare.
   * Extending {@link ClassCastException} may seem odd, but it is required.
   */
  @VisibleForTesting