private static final long SPIN_THRESHOLD_NANOS = 1000L;

  private static final AtomicHelper ATOMIC_HELPER;

  static {
    AtomicHelper helper;
    Throwable thrownUnsafeFailure = null;
    Throwable thrownAtomicReferenceFieldUpdaterFailure = null;

    try {
      helper = new UnsafeAtomicHelper();
    } catch (Exception | Error unsafeFailure) { // sneaky checked exception

        },
        (Multiset<E> multiset) -> copyOfSortedEntries(comparator, multiset.entrySet()));
  }

  @SuppressWarnings({"AndroidJdkLibsChecker", "Java7ApiChecker"})
  @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