*
   * <p>The returned array will be "safe" in that no references to it are maintained by this queue.
   * (In other words, this method must allocate a new array). The caller is thus free to modify the
   * returned array.
   *
   * <p>This method acts as bridge between array-based and collection-based APIs.
   *
   * @return an array containing all of the elements in this queue
   */

 * types, and also for interfaces and public classes that have public parameter-less constructors.
 * When the non-null default value for a particular parameter type cannot be provided by {@code
 * NullPointerTester}, the caller can provide a custom non-null default value for the parameter type
 * via {@link #setDefault}.
 *
 * @author Kevin Bourrillion
 * @since 10.0
 */
@GwtIncompatible
@J2ktIncompatible
@ElementTypesAreNonnullByDefault

     * newFuture is a future that completes after this and all prior tasks are done.
     * oldFuture is the previous task's newFuture.
     * outputFuture is the future we return to the caller, a nonCancellationPropagating taskFuture.
     *
     * newFuture is guaranteed to only complete once all tasks previously submitted to this instance