}

    @SuppressWarnings("unchecked") // proxy for a generic class
    <V1, V2, V3, V4, V5, U> ClosingFunction5<V1, V2, V3, V4, V5, U> waitFor(
        ClosingFunction5<V1, V2, V3, V4, V5, U> closingFunction5) {
      return waitFor(closingFunction5, ClosingFunction5.class);
    }

    <T> T waitFor(final T delegate, final Class<T> type) {
      checkState(proxy == null);

    }

    @SuppressWarnings("unchecked") // proxy for a generic class
    <V1, V2, V3, V4, V5, U> ClosingFunction5<V1, V2, V3, V4, V5, U> waitFor(
        ClosingFunction5<V1, V2, V3, V4, V5, U> closingFunction5) {
      return waitFor(closingFunction5, ClosingFunction5.class);
    }

    <T> T waitFor(final T delegate, final Class<T> type) {
      checkState(proxy == null);

     * @param <V4> the type returned by the fourth future
     * @param <V5> the type returned by the fifth future
     * @param <U> the type returned by the function
     */
    public interface ClosingFunction5<
        V1 extends @Nullable Object,
        V2 extends @Nullable Object,
        V3 extends @Nullable Object,
        V4 extends @Nullable Object,
        V5 extends @Nullable Object,