@ElementTypesAreNonnullByDefault
public abstract class FluentFuture<V extends @Nullable Object>
    extends GwtFluentFutureCatchingSpecialization<V> {

  /**
   * A less abstract subclass of AbstractFuture. This can be used to optimize setFuture by ensuring
   * that {@link #get} calls exactly the implementation of {@link AbstractFuture#get}.
   */
  abstract static class TrustedFuture<V extends @Nullable Object> extends FluentFuture<V>