if (isCancelled()) {
      builder.append("CANCELLED");
    } else if (isDone()) {
      addDoneString(builder);
    } else {
      String pendingDescription;
      try {
        pendingDescription = pendingToString();
      } catch (RuntimeException e) {
        // Don't call getMessage or toString() on the exception, in case the exception thrown by the
        // subclass is implemented with bugs similar to the subclass.

    this.inputFuture = null;
    this.function = null;
  }

  @Override
  @CheckForNull
  protected String pendingToString() {
    @RetainedLocalRef ListenableFuture<? extends I> localInputFuture = inputFuture;
    @RetainedLocalRef F localFunction = function;
    String superString = super.pendingToString();
    String resultString = "";
    if (localInputFuture != null) {

  }

  @Override
  @CheckForNull
  protected String pendingToString() {
    @RetainedLocalRef ListenableFuture<? extends V> localInputFuture = inputFuture;
    @RetainedLocalRef Class<X> localExceptionType = exceptionType;
    @RetainedLocalRef F localFallback = fallback;
    String superString = super.pendingToString();
    String resultString = "";
    if (localInputFuture != null) {

  }

  public void testToString_notDone() throws Exception {
    AbstractFuture<Object> testFuture =
        new AbstractFuture<Object>() {
          @Override
          public String pendingToString() {
            return "cause=[Because this test isn't done]";
          }
        };
    assertThat(testFuture.toString())
        .matches(

     */
  }

  @Override
  @CheckForNull
  protected final String pendingToString() {
    @RetainedLocalRef ImmutableCollection<? extends Future<?>> localFutures = futures;
    if (localFutures != null) {
      return "futures=" + localFutures;
    }
    return super.pendingToString();
  }

  /**

      setStackTrace(new StackTraceElement[0]);
      return this; // no stack trace, wouldn't be useful anyway
    }
  }

  @Override
  @CheckForNull
  protected String pendingToString() {
    @RetainedLocalRef ListenableFuture<? extends V> localInputFuture = delegateRef;
    @RetainedLocalRef ScheduledFuture<?> localTimer = timer;
    if (localInputFuture != null) {

      if (localDelegate != null) {
        setFuture(localDelegate);
      }
    }

    @Override
    @CheckForNull
    protected String pendingToString() {
      @RetainedLocalRef ListenableFuture<V> localDelegate = delegate;
      if (localDelegate != null) {
        return "delegate=[" + localDelegate + "]";
      }
      return null;
    }

          // Any Exception is either a RuntimeException or sneaky checked exception.
          setException(t);
          throw t;
        }
      }

      @Override
      protected String pendingToString() {
        return "task=[" + delegate + "]";
      }
    }
  }

  /*
   * This following method is a modified version of one found in

      if (localDelegate != null) {
        setFuture(localDelegate);
      }
    }

    @Override
    @CheckForNull
    protected String pendingToString() {
      @RetainedLocalRef ListenableFuture<V> localDelegate = delegate;
      if (localDelegate != null) {
        return "delegate=[" + localDelegate + "]";
      }
      return null;
    }