latch.countDown();

    exec.shutdown();
    exec.awaitTermination(100, MILLISECONDS);
  }

  /**
   * Tests that all listeners complete, even if they were added before or after the future was
   * finishing. Also acts as a concurrency test to make sure the locking is done correctly when a
   * future is finishing so that no listeners can be lost.
   */

 *
 * <p>The classes in this package include:
 *
 * <h2>Immutable collections</h2>
 *
 * These are collections whose contents will never change. They also offer a few additional
 * guarantees (see {@link ImmutableCollection} for details). Implementations are available for both
 * the JDK collection types and the Guava collection types (listed below).
 *

 *
 * <p>The classes in this package include:
 *
 * <h2>Immutable collections</h2>
 *
 * These are collections whose contents will never change. They also offer a few additional
 * guarantees (see {@link ImmutableCollection} for details). Implementations are available for both
 * the JDK collection types and the Guava collection types (listed below).
 *

Linux containers run using the same Linux kernel of the host (machine, virtual machine, cloud server, etc). This just means that they are very lightweight (compared to full virtual machines emulating an entire operating system).

 * {@link AsyncEventBus}.)
 *
 * <h2>Subscriber Methods</h2>
 *
 * <p>Event subscriber methods must accept only one argument: the event.
 *
 * <p>Subscribers should not, in general, throw. If they do, the EventBus will catch and log the
 * exception. This is rarely the right solution for error handling and should not be relied upon; it
 * is intended solely to help find problems during development.
 *

            alternatingKeysAndValues[previousKeyIndex ^ 1] = value;
            continue entries;
          }
        }
        if (outI < i) { // if outI == i don't bother writing the values back where they came from
          alternatingKeysAndValues[outKeyIndex] = key;
          alternatingKeysAndValues[outKeyIndex ^ 1] = value;
        }
        outI++;
      }

 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code
 * default} methods. Instead, it inherits their default implementations. When those implementations
 * invoke methods, they invoke methods on the {@code ForwardingMultimap}.
 *
 * @author Robert Konigsberg
 * @since 2.0
 */
@GwtCompatible
public abstract class ForwardingMultimap<K extends @Nullable Object, V extends @Nullable Object>

   * documentation for {@link Collection}:
   *
   * <blockquote>
   *
   * "Some collection implementations have restrictions on the elements that they may contain. For
   * example, some implementations prohibit null elements, and some have restrictions on the types
   * of their elements."
   *
   * </blockquote>
   */
  RESTRICTS_ELEMENTS,

  /**

 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code
 * default} methods. Instead, it inherits their default implementations. When those implementations
 * invoke methods, they invoke methods on the {@code ForwardingMultimap}.
 *
 * @author Robert Konigsberg
 * @since 2.0
 */
@GwtCompatible
public abstract class ForwardingMultimap<K extends @Nullable Object, V extends @Nullable Object>

  }

  /**
   * Returns the {@linkplain #getSampleElements() sample elements} as ordered by {@link
   * TestContainerGenerator#order(List)}. Tests should use this method only if they declare
   * requirement {@link com.google.common.collect.testing.features.CollectionFeature#KNOWN_ORDER}.
   */
  protected List<E> getOrderedElements() {
    List<E> list = new ArrayList<>();