* sum that is used for purposes such as collecting statistics, not for fine-grained synchronization
 * control. Under low update contention, the two classes have similar characteristics. But under
 * high contention, expected throughput of this class is significantly higher, at the expense of
 * higher space consumption.
 *
 * <p>This class extends {@link Number}, but does not define methods such as {@code

    Set<Feature<?>> features = Helpers.copyToSet(getFeatures());
    @SuppressWarnings("rawtypes") // class literals
    List<Class<? extends AbstractTester>> testers = getTesters();

    logger.fine(" Testing: " + name);

    // Split out all the specified sizes.
    Set<Feature<?>> sizesToTest = Helpers.<Feature<?>>copyToSet(CollectionSize.values());
    sizesToTest.retainAll(features);

          if (newValue == 0) {
            // Just CASed to 0; remove the entry to clean up the map. If the removal fails,
            // another thread has already replaced it with a new counter, which is fine.
            countMap.remove(element, existingCounter);
          }
          return oldValue;
        }
      } else {
        return 0;
      }
    }
  }

  /**

   */

  private int[] requirePredecessors() {
    return requireNonNull(predecessor);
  }

  private int[] requireSuccessors() {
    return requireNonNull(successor);
  }

  /*
   * We don't define getPredecessor+getSuccessor and setPredecessor+setSuccessor here because
   * they're defined above -- including logic to add and subtract 1 to map between the values stored

              "To help optimizers, any class that inherits a package-private writeReplace() method"
                  + " should override that method.\n"
                  + "(An override that delegates to the supermethod is fine.)\n"
                  + "%s has no such override despite inheriting writeReplace() from %s",
              clazz.getName(), supersWithPackagePrivateWriteReplace.get().getName())
          .fail();
    }
  }

              "To help optimizers, any class that inherits a package-private writeReplace() method"
                  + " should override that method.\n"
                  + "(An override that delegates to the supermethod is fine.)\n"
                  + "%s has no such override despite inheriting writeReplace() from %s",
              clazz.getName(), supersWithPackagePrivateWriteReplace.get().getName())
          .fail();
    }
  }

  //    assigned prior to calling addListener, and addListener happens-before any invocation of the
  //    listener. Notably, this means that 'volatile' is unnecessary to make 'inputFuture' visible
  //    to the listener.
  //
  // 2. In done() where we may propagate cancellation to the input. In this case it is _not_ fine.

 *
 * <p><b>Note:</b> In some cases the differences explained below can be subtle. When it's unclear
 * which approach to use, <b>don't worry</b> too much about it; just pick something that seems
 * reasonable and it will be fine.
 *
 * <ul>
 *   <li>If checking whether the <i>caller</i> has violated your method or constructor's contract
 *       (such as by passing an invalid argument), use the utilities of the {@link Preconditions}

       * NullPointerTester tests that they have.
       */
      ignoredMembers.add(Converter.class.getMethod("apply", Object.class));
    } catch (NoSuchMethodException shouldBeImpossible) {
      // OK, fine: If it doesn't exist, then there's chance that we're going to be asked to test it.
    }
  }

  /**
   * Sets a default value that can be used for any parameter of type {@code type}. Returns this
   * object.
   */

        // We only ever register ArrayReferences with the queue so this is always safe.
        ArrayReference<? extends L> arrayRef = (ArrayReference<? extends L>) ref;
        // Try to clear out the array slot, n.b. if we fail that is fine, in either case the
        // arrayRef will be out of the array after this step.
        locks.compareAndSet(arrayRef.index, arrayRef, null);
      }
    }

    @Override
    public int size() {