/**
   * An object that can capture objects to be closed later, when a {@link ClosingFuture} pipeline is
   * done.
   */
  public static final class DeferredCloser {
    @RetainedWith private final CloseableList list;

    DeferredCloser(CloseableList list) {
      this.list = list;
    }

    /**
     * Captures an object to be closed when a {@link ClosingFuture} pipeline is done.
     *