// sanity check on construction of copyOfModifiedSet
    assertThat(wrappedSet).isEqualTo(copyOfModifiedSet);

    // setToTest should throw when it calls equals(), or equals is called on it, except for itself
    assertThat(setToTest).isEqualTo(setToTest);
    assertThrows(IllegalStateException.class, () -> setToTest.equals(wrappedSet));

     */
    final Stack<E> previousElements = new Stack<>();

    /**
     * {@link #nextElements} if {@code next()} was called more recently then {@code previous},
     * {@link #previousElements} if the reverse is true, or -- overriding both of these -- {@code
     * null} if {@code remove()} or {@code add()} has been called more recently than either. We use
     * this to determine which stack to pop from on a call to {@code remove()} (or to pop from and

 *
 * Other exception types cancel the current call:
 *
 *  * For synchronous calls made with [Call.execute], the exception is propagated to the caller.
 *
 *  * For asynchronous calls made with [Call.enqueue], an [IOException] is propagated to the caller
 *    indicating that the call was canceled. The interceptor's exception is delivered to the current

  Installing Maven
  ----------------

  For complete documentation see https://maven.apache.org/download.html#Installation

  Licensing
  ---------

  Please see the file called LICENSE.

  Maven URLS
  ----------

  Home Page:          https://maven.apache.org
  Downloads:          https://maven.apache.org/download.html
  Release Notes:      https://maven.apache.org/docs/history.html

   * resizing.
   *
   * @throws IllegalArgumentException if {@code size} is negative
   */
  @J2ktIncompatible
  public static ByteArrayDataOutput newDataOutput(int size) {
    // When called at high frequency, boxing size generates too much garbage,
    // so avoid doing that if we can.
    checkArgument(size >= 0, "Invalid size: %s", size);
    return newDataOutput(new ByteArrayOutputStream(size));
  }

 * controls the order in which events are dispatched, while the executor controls how (i.e. on which
 * thread) the subscriber is actually called when an event is dispatched to it.
 *
 * @author Colin Decker
 */
abstract class Dispatcher {

  /**
   * Returns a dispatcher that queues events that are posted reentrantly on a thread that is already

 * instance contains a list of listeners, each with an associated {@code Executor}, and guarantees
 * that every {@code Runnable} that is {@linkplain #add added} will be executed after {@link
 * #execute()} is called. Any {@code Runnable} added after the call to {@code execute} is still
 * guaranteed to execute. There is no guarantee, however, that listeners will be executed in the
 * order that they are added.
 *

    assertThat(INSTANCE.get('a', 1)).isNull();
  }

  public void testIsEmpty() {
    assertTrue(INSTANCE.isEmpty());
  }

  public void testCellSet() {
    assertEquals(ImmutableSet.of(), INSTANCE.cellSet());
  }

  public void testColumn() {
    assertEquals(ImmutableMap.of(), INSTANCE.column(1));
  }

  public void testColumnKeySet() {
    assertEquals(ImmutableSet.of(), INSTANCE.columnKeySet());
  }

   * elements than the collection), the element in the array immediately following the end of the
   * collection is set to {@code null}. This is useful in determining the length of the collection
   * <i>only</i> if the caller knows that the collection does not contain any null elements.
   *
   * <p>This method returns the elements in the order they are returned by the collection's
   * iterator.
   *

1. Creating a PR and observing the presubmit test results
2. Running the CI scripts locally, as explained below
3. **Google employees only**: Google employees can use an internal-only tool
called "MLCI" that makes testing more convenient: it can execute any full CI job
against a pending change. Search for "MLCI" internally to find it.

You may invoke a CI script of your choice by following these instructions:

```bash