* acquire other locks, risking deadlocks.
   */
  @CanIgnoreReturnValue
  @Override
  public boolean cancel(boolean mayInterruptIfRunning) {
    @RetainedLocalRef Object localValue = value();
    boolean rValue = false;
    if (localValue == null | localValue instanceof DelegatingToFuture) {
      // Try to delay allocating the exception. At this point we may still lose the CAS, but it is
      // certainly less likely.