* checkNotNull *should* be annotated to require it to be non-null.
   *
   * However, for a variety of reasons, Google developers have written a ton of code over the past
   * decade that assumes that they can use checkNotNull for non-precondition checks. I had hoped to
   * take a principled stand on this, but the amount of such code is simply overwhelming. To avoid

      fail("IllegalArgumentException expected");
    } catch (IllegalArgumentException expected) {
    }

    // These results are all incorrect, but there's no way (short of iterating over the result)
    // to verify that with an arbitrary ordering or comparator.
    assertEquals(ImmutableSortedSet.of(2, 4), Sets.subSet(set, Range.atLeast(4)));

    // Only report scheduling delay if larger than our spin threshold - otherwise it's just noise
    if (remainingNanos + SPIN_THRESHOLD_NANOS < 0) {
      // We over-waited for our timeout.
      message += " (plus ";
      long overWaitNanos = -remainingNanos;
      long overWaitUnits = unit.convert(overWaitNanos, TimeUnit.NANOSECONDS);

      fail("IllegalArgumentException expected");
    } catch (IllegalArgumentException expected) {
    }

    // These results are all incorrect, but there's no way (short of iterating over the result)
    // to verify that with an arbitrary ordering or comparator.
    assertEquals(ImmutableSortedMap.of(2, 0, 4, 0), Maps.subMap(map, Range.atLeast(4)));

      fail("IllegalArgumentException expected");
    } catch (IllegalArgumentException expected) {
    }

    // These results are all incorrect, but there's no way (short of iterating over the result)
    // to verify that with an arbitrary ordering or comparator.
    assertEquals(ImmutableSortedMap.of(2, 0, 4, 0), Maps.subMap(map, Range.atLeast(4)));

  }

  /**
   * Returns an unmodifiable <b>view</b> of the union of two sets. The returned set contains all
   * elements that are contained in either backing set. Iterating over the returned set iterates
   * first over all the elements of {@code set1}, then over each element of {@code set2}, in order,
   * that is not contained in {@code set1}.
   *
   * <p>Results are undefined if {@code set1} and {@code set2} are sets based on different

   * LinkedListMultimap#create()}, {@link TreeMultimap#create()}, and {@link
   * TreeMultimap#create(Comparator, Comparator)} won't suffice.
   *
   * <p>Note: the multimap assumes complete ownership over of {@code map} and the collections
   * returned by {@code factory}. Those objects should not be manually updated and they should not
   * use soft, weak, or phantom references.
   *

      // though that isn't currently publicly documented.
      count++;
    }
    return count;
  }

  /**
   * Returns an iterator that cycles indefinitely over the elements of {@code iterable}.
   *
   * <p>The returned iterator supports {@code remove()} if the provided iterator does. After {@code