boolean isEmpty();

  /**
   * Returns the minimal range which {@linkplain Range#encloses(Range) encloses} all ranges in this
   * range set.
   *
   * @throws NoSuchElementException if this range set is {@linkplain #isEmpty() empty}
   */
  Range<C> span();

  // Views

  /**
   * Returns a view of the {@linkplain Range#isConnected disconnected} ranges that make up this

    }
  }

  @Override
  public Range<K> span() {
    if (ranges.isEmpty()) {
      throw new NoSuchElementException();
    }
    Range<K> firstRange = ranges.get(0);
    Range<K> lastRange = ranges.get(ranges.size() - 1);
    return Range.create(firstRange.lowerBound, lastRange.upperBound);
  }

  /**
   * Guaranteed to throw an exception and leave the {@code RangeMap} unmodified.

     *         specified version range.
     *         <p>
     *         The restrictions of the returned version range will be an intersection of the restrictions
     *         of this version range and the specified version range if both version ranges have
     *         restrictions. Otherwise, the restrictions on the returned range will be empty.
     *         </p>
     *         <p>

   * also be called their <i>union</i>. If they are not, note that the span might contain values
   * that are not contained in either input range.
   *
   * <p>Like {@link #intersection(Range) intersection}, this operation is commutative, associative
   * and idempotent. Unlike it, it is always well-defined for any two input ranges.
   */
  public Range<C> span(Range<C> other) {

  @GwtIncompatible // java.math.BigInteger
  public void testMean() {
    // Odd-sized ranges have an obvious mean
    assertMean(2, 1, 3);

    assertMean(-2, -3, -1);
    assertMean(0, -1, 1);
    assertMean(1, -1, 3);
    assertMean((1 << 30) - 1, -1, Integer.MAX_VALUE);

    // Even-sized ranges should prefer the lower mean
    assertMean(2, 1, 4);
    assertMean(-3, -4, -1);
    assertMean(0, -1, 2);

                                // MNG-2123: if the previous node was not a range, then it wouldn't have any available
                                // versions. We just clobbered the selected version above. (why? I have no idea.)
                                // So since we are here and this is ranges we must go figure out the version (for a
                                // third time...)

  }

  /**
   * This test attempts to cause a future to wait for longer than it was requested to from a timed
   * get() call. As measurements of time are prone to flakiness, it tries to assert based on ranges
   * derived from observing how much time actually passed for various operations.
   */
  @SuppressWarnings({"DeprecatedThreadMethods", "ThreadPriorityCheck"})
  @AndroidIncompatible // Thread.suspend

  public boolean encloses(Range<C> range) {
    checkNotNull(range);
    Entry<Cut<C>, Range<C>> floorEntry = rangesByLowerBound.floorEntry(range.lowerBound);
    return floorEntry != null && floorEntry.getValue().encloses(range);
  }

  @CheckForNull
  private Range<C> rangeEnclosing(Range<C> range) {
    checkNotNull(range);
    Entry<Cut<C>, Range<C>> floorEntry = rangesByLowerBound.floorEntry(range.lowerBound);

      remove(range);
      entriesByLowerBound.put(range.lowerBound, new RangeMapEntry<K, V>(range, value));
    }
  }

  @Override
  public void putCoalescing(Range<K> range, V value) {
    // don't short-circuit if the range is empty - it may be between two ranges we can coalesce.
    if (entriesByLowerBound.isEmpty()) {
      put(range, value);
      return;
    }

  /** Converts a Range to a GeneralRange. */
  @SuppressWarnings("rawtypes") // https://github.com/google/guava/issues/989
  static <T extends Comparable> GeneralRange<T> from(Range<T> range) {
    T lowerEndpoint = range.hasLowerBound() ? range.lowerEndpoint() : null;
    BoundType lowerBoundType = range.hasLowerBound() ? range.lowerBoundType() : OPEN;

    T upperEndpoint = range.hasUpperBound() ? range.upperEndpoint() : null;