&& hashCodeInsensitiveToArgReference(
              factory, args, i, generateDummyArg(param, newFreshValueGenerator()))) {
        // If the implementation uses identityHashCode(), referential equality is
        // probably intended. So no point in using an equal-but-different factory argument.
        // We check twice to avoid confusion caused by accidental hash collision.
        equalArgs.set(i, shouldBeEqualArg);
      }
    }

   * stream may perform better.
   *
   * @see Stream#concat(Stream, Stream)
   */
  @SuppressWarnings("unchecked") // could probably be avoided with a forwarding Spliterator
  @SafeVarargs
  public static <T extends @Nullable Object> Stream<T> concat(Stream<? extends T>... streams) {
    // TODO(lowasser): consider an implementation that can support SUBSIZED

    if (!iterator.hasNext()) {
      return Optional.absent();
    }

    /*
     * TODO(kevinb): consider whether this "optimization" is worthwhile. Users with SortedSets tend
     * to know they are SortedSets and probably would not call this method.
     */
    if (iterable instanceof SortedSet) {
      SortedSet<E> sortedSet = (SortedSet<E>) iterable;
      return Optional.of(sortedSet.last());
    }

    while (true) {

    if (!iterator.hasNext()) {
      return Optional.absent();
    }

    /*
     * TODO(kevinb): consider whether this "optimization" is worthwhile. Users with SortedSets tend
     * to know they are SortedSets and probably would not call this method.
     */
    if (iterable instanceof SortedSet) {
      SortedSet<E> sortedSet = (SortedSet<E>) iterable;
      return Optional.of(sortedSet.last());
    }

    while (true) {

    }

    @Override
    int expectedValueCollectionSize(int defaultExpectedValues, Iterable<?> values) {
      // Only trust the size of `values` if it is a Set and therefore probably already deduplicated.
      if (values instanceof Set<?>) {
        Set<?> collection = (Set<?>) values;
        return max(defaultExpectedValues, collection.size());
      } else {
        return defaultExpectedValues;

         * Thread.interrupt() (as discussed in InterruptibleTask). At the end of the day, it's
         * unlikely that cancel() will be slow, so we can probably get away with calling it while
         * holding a lock. Still, it would be nice to avoid somehow.
         */
        lock.lock();
        try {
          currentFuture.cancel(mayInterruptIfRunning);

           * -4294967296L = -9223372036854775808L!
           *
           * To be clear, this bug affects not the test's computation of the expected result but the
           * _actual prod code_. But it probably affects only unusual cases.
           */
          continue;
        }
        BigInteger expectedResult = valueOf(a).multiply(valueOf(b));
        boolean expectedSuccess = fitsInLong(expectedResult);

       * that behavior is undefined when the backing map is modified through another API. (It even
       * permits us to throw IllegalStateException. Maybe we should have done that, but we probably
       * shouldn't change now for fear of breaking people.)
       */
      return (lastKnownIndex == -1) ? unsafeNull() : value(lastKnownIndex);
    }

    @Override
    @ParametricNullness

		if n < 0 {
			panic(errNegativeRead)
		}
		if n == 0 {
			return 0, b.readErr()
		}
		b.w += n
	}

	// copy as much as we can
	// Note: if the slice panics here, it is probably because
	// the underlying reader returned a bad count. See issue 49795.
	n = copy(p, b.buf[b.r:b.w])
	b.r += n
	b.lastByte = int(b.buf[b.r-1])
	b.lastRuneSize = -1
	return n, nil
}

        // a cyclic edge: it's possible for two threads to simultaneous find
        // "safe" edges which together form a cycle. Preventing this race
        // condition efficiently without _introducing_ deadlock is probably
        // tricky. For now, just accept the race condition---missing a warning
        // now and then is still better than having no deadlock detection.