return blockingCallable.isRunning();
              }
            },
            directExecutor());

    // Wait for the first task to be started in the background. It will block until we explicitly
    // stop it.
    blockingCallable.waitForStart();

    // Give the second task a chance to (incorrectly) start up while the first task is running.
    assertThat(future2.isDone()).isFalse();

                return blockingCallable.isRunning();
              }
            },
            directExecutor());

    // Wait for the first task to be started in the background. It will block until we explicitly
    // stop it.
    blockingCallable.waitForStart();

    // Give the second task a chance to (incorrectly) start up while the first task is running.
    assertThat(future2.isDone()).isFalse();

 * @since 1.0
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public final class Charsets {
  private Charsets() {}

  /**
   * US-ASCII: seven-bit ASCII, the Basic Latin block of the Unicode character set (ISO646-US).
   *
   * <p><b>Java 7+ users:</b> this constant should be treated as deprecated; use {@link
   * java.nio.charset.StandardCharsets#US_ASCII} instead.
   *
   */

  protected void shutDown() throws Exception {}

  /**
   * Invoked to request the service to stop.
   *
   * <p>By default this method does nothing.
   *
   * <p>Currently, this method is invoked while holding a lock. If an implementation of this method
   * blocks, it can prevent this service from changing state. If you need to performing a blocking
   * operation in order to trigger shutdown, consider instead registering a listener and

    Collection<V> values = multimap.get(key); // Needn't be in synchronized block
    synchronized (multimap) { // Synchronizing on multimap, not values!
      Iterator<V> i = values.iterator(); // Must be in synchronized block
      while (i.hasNext()) {
        foo(i.next());
      }
    }
  }

  private static void foo(Object unused) {}

   * future changes to it will alter the behavior of the predicate.
   *
   * <p>This method can technically accept any {@code Collection<?>}, but using a typed collection
   * helps prevent bugs. This approach doesn't block any potential users since it is always possible
   * to use {@code Predicates.<Object>in()}.
   *
   * @param target the collection that may contain the function input
   */