@Override
      long treeAggregate(@CheckForNull AvlNode<?> root) {
        return (root == null) ? 0 : root.totalCount;
      }
    },
    DISTINCT {
      @Override
      int nodeAggregate(AvlNode<?> node) {
        return 1;
      }

      @Override
      long treeAggregate(@CheckForNull AvlNode<?> root) {
        return (root == null) ? 0 : root.distinctElements;
      }
    };

    name: "${{ matrix.root-pom }} on JDK ${{ matrix.java }} on ${{ matrix.os }}"
    strategy:
      matrix:
        os: [ ubuntu-latest ]
        java: [ 8, 11, 17, 21 ]
        root-pom: [ 'pom.xml', 'android/pom.xml' ]
        include:
          - os: windows-latest
            java: 21
            root-pom: pom.xml
    runs-on: ${{ matrix.os }}
    env:
      ROOT_POM: ${{ matrix.root-pom }}
    steps:

 *     throw new IllegalArgumentException("input is negative: " + value);
 *   }
 *   // calculate square root
 * }
 * }</pre>
 *
 * <p>to be replaced with the more compact
 *
 * <pre>{@code
 * public static double sqrt(double value) {
 *   checkArgument(value >= 0, "input is negative: %s", value);
 *   // calculate square root
 * }
 * }</pre>
 *
 * <p>so that a hypothetical bad caller of this method, such as:
 *

      }
      remainingNanos = endNanos - System.nanoTime();
    }

    String futureToString = toString();
    final String unitString = unit.toString().toLowerCase(Locale.ROOT);
    String message = "Waited " + timeout + " " + unit.toString().toLowerCase(Locale.ROOT);
    // Only report scheduling delay if larger than our spin threshold - otherwise it's just noise
    if (remainingNanos + SPIN_THRESHOLD_NANOS < 0) {

        Joiner.on(":")
            .join(
                "relative/path/to/some.jar",
                "/absolute/path/to/some.jar",
                "relative/path/to/class/root",
                "/absolute/path/to/class/root"));
    try {
      ImmutableList<URL> urls = ClassPath.parseJavaClassPath();

      assertThat(urls.get(0).getProtocol()).isEqualTo("file");

     */
    return ref == null ? Optional.absent() : Optional.fromNullable(enumClass.cast(ref.get()));
  }

  static String formatCompact4Digits(double value) {
    return String.format(Locale.ROOT, "%.4g", value);
  }

  static boolean stringIsNullOrEmpty(@CheckForNull String string) {
    return string == null || string.isEmpty();
  }

  /**

  @Deprecated
  public final FluentIterable<T> preOrderTraversal(final T root) {
    checkNotNull(root);
    return new FluentIterable<T>() {
      @Override
      public UnmodifiableIterator<T> iterator() {
        return preOrderIterator(root);
      }
    };
  }

  UnmodifiableIterator<T> preOrderIterator(T root) {
    return new PreOrderIterator(root);
  }

 *       block or a {@link ListenableFuture}.
 *   <li>Each other step is derived from one or more input steps. At each step, zero or more objects
 *       can be captured for later closing.
 *   <li>There is one last step (the root of the tree), from which you can extract the final result
 *       of the computation. After that result is available (or the computation fails), all objects
 *       captured by any of the steps in the pipeline are closed.
 * </ol>