} catch (SecurityException e) {
      generateCancellationCauses = false;
    }
    GENERATE_CANCELLATION_CAUSES = generateCancellationCauses;
  }

  /**
   * Tag interface marking trusted subclasses. This enables some optimizations. The implementation
   * of this interface must also be an AbstractFuture and must not override or expose for overriding
   * any of the public methods of ListenableFuture.
   */

    }
    try {
      ClosingFuture.whenAllSucceed(asList(closingFuture));
      fail();
    } catch (IllegalStateException expected) {
    }
  }

  /** Asserts that marking this step a final step throws {@link IllegalStateException}. */
  protected void assertFinalStepThrowsIllegalStateException(ClosingFuture<?> closingFuture) {
    try {
      closingFuture.finishToFuture();
      fail();

    }
    try {
      ClosingFuture.whenAllSucceed(asList(closingFuture));
      fail();
    } catch (IllegalStateException expected) {
    }
  }

  /** Asserts that marking this step a final step throws {@link IllegalStateException}. */
  protected void assertFinalStepThrowsIllegalStateException(ClosingFuture<?> closingFuture) {
    try {
      closingFuture.finishToFuture();
      fail();