/** Atomic compare-and-set of the {@link AggregateFutureState#seenExceptions} field. */
    abstract void compareAndSetSeenExceptions(
        AggregateFutureState<?> state, @CheckForNull Set<Throwable> expect, Set<Throwable> update);

    /** Atomic decrement-and-get of the {@link AggregateFutureState#remaining} field. */
    abstract int decrementAndGetRemainingCount(AggregateFutureState<?> state);
  }

import static com.google.common.collect.Sets.newHashSet;

import java.util.Set;
import org.checkerframework.checker.nullness.qual.Nullable;

/** Emulation of AggregateFutureState. */
@ElementTypesAreNonnullByDefault
abstract class AggregateFutureState<OutputT extends @Nullable Object>
    extends AbstractFuture.TrustedFuture<OutputT> {
  // Lazily initialized the first time we see an exception; not released until all the input futures

    /** Atomic compare-and-set of the {@link AggregateFutureState#seenExceptions} field. */
    abstract void compareAndSetSeenExceptions(
        AggregateFutureState<?> state, @CheckForNull Set<Throwable> expect, Set<Throwable> update);

    /** Atomic decrement-and-get of the {@link AggregateFutureState#remaining} field. */
    abstract int decrementAndGetRemainingCount(AggregateFutureState<?> state);
  }

    "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