* <h4>Automatically closing</h4>
 *
 * You can extract a {@link Future} that represents the result of the last step in the pipeline by
 * calling {@link #finishToFuture()}. All objects the pipeline has captured for closing will begin
 * to be closed asynchronously <b>after</b> the returned {@code Future} is done: the future
 * completes before closing starts, rather than once it has finished.
 *
 * <pre>{@code
 * FluentFuture<UserName> userName =

  @GwtIncompatible(value = "java.util.regex.Pattern")
  public static Predicate<CharSequence> contains(Pattern pattern) {
    return new ContainsPatternPredicate(new JdkPattern(pattern));
  }

  // End public API, begin private implementation classes.

  // Package private for GWT serialization.
  enum ObjectPredicate implements Predicate<@Nullable Object> {
    /** @see Predicates#alwaysTrue() */
    ALWAYS_TRUE {
      @Override