.add("in", "the", "quick", "jumped", "over", "a")
            .build();
    assertTrue(set.headSet("a") instanceof ImmutableSortedSet);
    assertTrue(set.headSet("fish") instanceof ImmutableSortedSet);
    assertThat(set.headSet("fish")).containsExactly("a", "in", "the").inOrder();
    assertThat(set.headSet("california"))
        .containsExactly("a", "in", "the", "over", "quick", "jumped")
        .inOrder();

   * order. The sorting algorithm used is stable, so elements that compare as equal will stay in the
   * order in which they appear in the input.
   *
   * <p>If your data has no duplicates, or you wish to deduplicate elements, use {@code
   * ImmutableSortedSet.copyOf(elements)}; if you want a {@code List} you can use its {@code
   * asList()} view.
   *

   *
   * <p>By default, this method throws {@link InsecureRecursiveDeleteException} if it can't
   * guarantee the security of recursive deletes. If you wish to allow the recursive deletes anyway,
   * pass {@link RecursiveDeleteOption#ALLOW_INSECURE} to this method to override that behavior.
   *

   *
   * <p>By default, this method throws {@link InsecureRecursiveDeleteException} if it can't
   * guarantee the security of recursive deletes. If you wish to allow the recursive deletes anyway,
   * pass {@link RecursiveDeleteOption#ALLOW_INSECURE} to this method to override that behavior.
   *

      case HALF_DOWN:
      case HALF_UP:
      case HALF_EVEN:
        long sqrtFloor = guess - ((x < guessSquared) ? 1 : 0);
        long halfSquare = sqrtFloor * sqrtFloor + sqrtFloor;
        /*
         * We wish to test whether or not x <= (sqrtFloor + 0.5)^2 = halfSquare + 0.25. Since both x
         * and halfSquare are integers, this is equivalent to testing whether or not x <=
         * halfSquare. (We have to deal with overflow, though.)

       * need to clear our reference to the TimeoutFuture is the reason we use a *static* nested
       * class with a manual reference back to the "containing" class.)
       *
       * This has the nice-ish side effect of limiting reentrancy: run() calls
       * timeoutFuture.setException() calls run(). That reentrancy would already be harmless, since

 * </ul>
 *
 * <p>Static convenience methods called {@code meanOf} are also provided for users who wish to
 * calculate <i>only</i> the mean.
 *
 * <p><b>Java 8+ users:</b> If you are not using any of the variance statistics, you may wish to use
 * built-in JDK libraries instead of this class.
 *
 * @author Pete Gillin
 * @author Kevin Bourrillion
 * @since 20.0
 */

      case HALF_DOWN:
      case HALF_UP:
      case HALF_EVEN:
        BigInteger halfSquare = sqrtFloor.pow(2).add(sqrtFloor);
        /*
         * We wish to test whether or not x <= (sqrtFloor + 0.5)^2 = halfSquare + 0.25. Since both x
         * and halfSquare are integers, this is equivalent to testing whether or not x <=
         * halfSquare.
         */

      case HALF_DOWN:
      case HALF_UP:
      case HALF_EVEN:
        long sqrtFloor = guess - ((x < guessSquared) ? 1 : 0);
        long halfSquare = sqrtFloor * sqrtFloor + sqrtFloor;
        /*
         * We wish to test whether or not x <= (sqrtFloor + 0.5)^2 = halfSquare + 0.25. Since both x
         * and halfSquare are integers, this is equivalent to testing whether or not x <=
         * halfSquare. (We have to deal with overflow, though.)

   * order. The sorting algorithm used is stable, so elements that compare as equal will stay in the
   * order in which they appear in the input.
   *
   * <p>If your data has no duplicates, or you wish to deduplicate elements, use {@code
   * ImmutableSortedSet.copyOf(elements)}; if you want a {@code List} you can use its {@code
   * asList()} view.
   *