if (submittingTaskQueue.thread == submitting) {
          sequencer = null;
          // Submit from inside a reentrant submit. We don't know if this one will be reentrant (and
          // can't know without submitting something to the executor) so queue to run iteratively.
          // Task must be null, since each execution on this executor can only produce one more
          // execution.
          checkState(submittingTaskQueue.nextTask == null);

  }

  private void swap(int i, int j) {
    T tmp = buffer[i];
    buffer[i] = buffer[j];
    buffer[j] = tmp;
  }

  /*
   * While the current implementation returns `this`, that's not something we mean to guarantee.
   * Anyway, the purpose of this method is to implement a BinaryOperator combiner for a Collector,
   * so its return value will get used naturally.
   */

   */
  protected final class MultiExceptionListIterator implements ListIterator<E> {
    // TODO: track seen elements when order isn't guaranteed
    // TODO: verify contents afterward
    // TODO: something shiny and new instead of Stack
    // TODO: test whether null is supported (create a Feature)
    /**
     * The elements to be returned by future calls to {@code next()}, with the first at the top of
     * the stack.

 * }
 *
 * <h3>Comparison to alternatives</h3>
 *
 * <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

 *   <li><b>Convenience methods:</b> These are implementations of common operations that are
 *       typically implemented by opening a reader using one of the methods in the first category,
 *       doing something and finally closing the reader that was opened.
 * </ul>
 *
 * <p>Several methods in this class, such as {@link #readLines()}, break the contents of the source

 *   <li><b>Convenience methods:</b> These are implementations of common operations that are
 *       typically implemented by opening a reader using one of the methods in the first category,
 *       doing something and finally closing the reader that was opened.
 * </ul>
 *
 * <p>Several methods in this class, such as {@link #readLines()}, break the contents of the source

@DoNotMock("Use ImmutableList.of or another implementation")
@GwtCompatible
@SuppressWarnings("serial") // we're overriding default serialization
// TODO(kevinb): I think we should push everything down to "BaseImmutableCollection" or something,
// just to do everything we can to emphasize the "practically an interface" nature of this class.
public abstract class ImmutableCollection<E> extends AbstractCollection<E> implements Serializable {
  /*

 *     .build();
 * ```
 *
 * ## Force a Cache Response
 *
 * Sometimes you'll want to show resources if they are available immediately, but not otherwise.
 * This can be used so your application can show *something* while waiting for the latest data to be
 * downloaded. To restrict a request to locally-cached resources, add the `only-if-cached`
 * directive:
 *
 * ```java
 * Request request = new Request.Builder()

   */
  protected final class MultiExceptionListIterator implements ListIterator<E> {
    // TODO: track seen elements when order isn't guaranteed
    // TODO: verify contents afterward
    // TODO: something shiny and new instead of Stack
    // TODO: test whether null is supported (create a Feature)
    /**
     * The elements to be returned by future calls to {@code next()}, with the first at the top of
     * the stack.

    }
    for (int j = 0; j < 1000; j++) {
      builder.add(9);
    }
    ImmutableSortedSet<Integer> unused = builder.build();
    assertThat(compares[0]).isAtMost(10000);
    // hopefully something quadratic would have more digits
  }