throw new UnsupportedOperationException();
  }

  /**
   * Not supported. <b>You are attempting to create a map that may contain a non-{@code Comparable}
   * key.</b> Proper calls will resolve to the version in {@code ImmutableSortedMap}, not this dummy
   * version.
   *
   * @throws UnsupportedOperationException always
   * @deprecated <b>Pass a key of type {@code Comparable} to use {@link

    throw new UnsupportedOperationException();
  }

  /**
   * Not supported. <b>You are attempting to create a set that may contain a non-{@code Comparable}
   * element.</b> Proper calls will resolve to the version in {@code ImmutableSortedSet}, not this
   * dummy version.
   *
   * @throws UnsupportedOperationException always
   * @deprecated <b>Pass a parameter of type {@code Comparable} to use {@link

    }
    return Iterators.contains(iterable.iterator(), element);
  }

  /**
   * Removes, from an iterable, every element that belongs to the provided collection.
   *
   * <p>This method calls {@link Collection#removeAll} if {@code iterable} is a collection, and
   * {@link Iterators#removeAll} otherwise.
   *
   * @param removeFrom the iterable to (potentially) remove elements from

       * safe; if this Builder is used further, it will grow the entries array (so it can't
       * affect the original array), and future build() calls will always copy any entry
       * objects that cannot be safely reused.
       */
      // localAlternatingKeysAndValues is an alias for the alternatingKeysAndValues field, except if
      // we end up removing duplicates in a copy of the array.

   */
  interface Trusted<V extends @Nullable Object> extends ListenableFuture<V> {}

  /**
   * A less abstract subclass of AbstractFuture. This can be used to optimize setFuture by ensuring
   * that {@link #get} calls exactly the implementation of {@link AbstractFuture#get}.
   */
  abstract static class TrustedFuture<V extends @Nullable Object> extends AbstractFuture<V>
      implements Trusted<V> {
    @CanIgnoreReturnValue

    public String toString() {
      return "Ordering.arbitrary()";
    }

    /*
     * We need to be able to mock identityHashCode() calls for tests, because it
     * can take 1-10 seconds to find colliding objects. Mocking frameworks that
     * can do magic to mock static method calls still can't do so for a system
     * class, so we need the indirection. In production, Hotspot should still

    return MoreObjects.firstNonNull(asMap().remove(key), unmodifiableEmptyCollection());
  }

  Collection<V> unmodifiableEmptyCollection() {
    // These return false, rather than throwing a UOE, on remove calls.
    return (unfiltered instanceof SetMultimap)
        ? Collections.<V>emptySet()
        : Collections.<V>emptyList();
  }

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

  @IgnoreJRERequirement // helper for toImmutableSortedMultiset
  /*
   * If we make these calls inline inside toImmutableSortedMultiset, we get an Animal Sniffer error,
   * despite the @IgnoreJRERequirement annotation there. My assumption is that, because javac
   * generates a synthetic method for the body of the lambda, the actual method calls that Animal
   * Sniffer is flagging don't appear inside toImmutableSortedMultiset but rather inside that

   *   <li>If {@code equivalent(x, y)} and {@code equivalent(y, z)} are both true, then {@code
   *       equivalent(x, z)} is also true (<i>transitive</i> property)
   * </ul>
   *
   * <p>Note that all calls to {@code equivalent(x, y)} are expected to return the same result as
   * long as neither {@code x} nor {@code y} is modified.
   */
  public final boolean equivalent(@CheckForNull T a, @CheckForNull T b) {
    if (a == b) {

      return uncheckedCastNullableTToT(peekedElement);
    }
  }

  /**
   * Returns a {@code PeekingIterator} backed by the given iterator.
   *
   * <p>Calls to the {@code peek} method with no intervening calls to {@code next} do not affect the
   * iteration, and hence return the same object each time. A subsequent call to {@code next} is
   * guaranteed to return the same object again. For example:
   *