import org.jspecify.annotations.Nullable;

abstract class AbstractFutureState<V extends @Nullable Object> extends InternalFutureFailureAccess
    implements ListenableFuture<V> {
  final boolean casListeners(@Nullable Listener expect, Listener update) {
    if (listeners == expect) {
      listeners = update;
      return true;
    }
    return false;
  }

  final @Nullable Listener gasListeners(Listener update) {