"ShortCircuitBoolean")
abstract class AggregateFuture<InputT extends @Nullable Object, OutputT extends @Nullable Object>
    extends AggregateFutureState<OutputT> {
  private static final LazyLogger logger = new LazyLogger(AggregateFuture.class);

  /**
   * The input futures. After {@link #init}, this field is read only by {@link #afterDone()} (to