// don't execute 'immediately'.  By checking isDone here we avoid that.
    // A corollary to all that is that we don't need to check isDone inside the loop because if we
    // get into the loop we know that we weren't done when we entered and therefore we aren't under
    // an obligation to execute 'immediately'.
    if (!isDone()) {
      Listener oldHead = listeners;

          // We're careful to put only K instances in.
          K[] sortedKs = (K[]) sortedKeys;
          Arrays.sort(sortedKs, comparator);
          Object[] sortedValues = new Object[size];

          // We might, somehow, be able to reorder values in-place.  But it doesn't seem like
          // there's a way around creating the separate sortedKeys array, and if we're allocating

   */
  public static void checkState(
      boolean expression,
      /*
       * TODO(cpovirk): Consider removing @CheckForNull here, as we've done with the other methods'
       * errorMessageTemplate parameters: It is unlikely that callers intend for their string
       * template to be null (though we do handle that case gracefully at runtime). I've left this
       * one as it is because one of our users has defined a wrapper API around Preconditions,

  //    definitely observe all earlier writes, but we still have no guarantee that done() would see
  //    the initial write (just stronger guarantees if it does).
  //
  // See: http://cs.oswego.edu/pipermail/concurrency-interest/2015-January/013800.html
  // For a (long) discussion about this specific issue and the general futility of life.
  //
  // For the time being we are OK with the problem discussed above since it requires a caller to

      if (oldCapacity >= MAXIMUM_CAPACITY) {
        return;
      }

      /*
       * Reclassify nodes in each list to new Map. Because we are using power-of-two expansion, the
       * elements from each bin must either stay at same index, or move with a power of two offset.
       * We eliminate unnecessary node creation by catching cases where old nodes can be reused

      // Warning: this is broken if size() == 0, so it is critical that we
      // substitute an empty ImmutableSet to the user in place of this

      // It's a weird formula, but tests prove it works.
      int adjust = size() - 1;
      for (int i = 0; i < axes.size(); i++) {
        adjust *= 31;
        adjust = ~~adjust;
        // in GWT, we have to deal with integer overflow carefully
      }
      int hash = 1;

         * be used with collections that may contain null. This collection never contains nulls, so
         * we could return `Object[]`. But this class is private and J2KT cannot change return types
         * in overrides, so we declare `@Nullable Object[]` as the return type.
         */
        return ObjectArrays.toArrayImpl(delegate());
      }
    }

    @Override

    }
  }

  private static Iterator<Integer> iterateOver(int... values) {
    // Note: Ints.asList's iterator does not support remove which we need for testing.
    return new ArrayList<>(Ints.asList(values)).iterator();
  }

  public void testElementsEqual() {
    Iterable<?> a;
    Iterable<?> b;

    // Base case.

         * Don't store a new Iterator until we know the user can't remove() the last returned
         * element anymore. Otherwise, when we remove from the old iterator, we may be invalidating
         * the new one. The result is a ConcurrentModificationException or other bad behavior.
         *
         * (If we decide that we really, really hate allocating two Iterators per cycle instead of