private abstract static class RawTypeConsistencyTester<T extends Enum<T> & CharSequence> {
    abstract T returningT();

    abstract void acceptT(T t);

    abstract <X extends T> X returningX();

    abstract <X> void acceptX(X x);

    abstract <T2 extends Enum<T2> & CharSequence> T2 returningT2();

    abstract <T2 extends CharSequence & Iterable<T2>> void acceptT2(T2 t2);

  private abstract static class RawTypeConsistencyTester<T extends Enum<T> & CharSequence> {
    abstract T returningT();

    abstract void acceptT(T t);

    abstract <X extends T> X returningX();

    abstract <X> void acceptX(X x);

    abstract <T2 extends Enum<T2> & CharSequence> T2 returningT2();

    abstract <T2 extends CharSequence & Iterable<T2>> void acceptT2(T2 t2);

    if (instance != null) {
      return (ListenableFuture<V>) instance;
    }
    return new ImmediateCancelledFuture<>();
  }

  /**
   * Executes {@code callable} on the specified {@code executor}, returning a {@code Future}.
   *
   * @throws RejectedExecutionException if the task cannot be scheduled for execution
   * @since 28.2
   */
  public static <O extends @Nullable Object> ListenableFuture<O> submit(

      @Override
      T transform(@ParametricNullness F from) {
        return function.apply(from);
      }
    };
  }

  /**
   * Advances {@code iterator} {@code position + 1} times, returning the element at the {@code
   * position}th position.
   *
   * @param position position of the element to return
   * @return the element at the specified position in {@code iterator}

      @Override
      T transform(@ParametricNullness F from) {
        return function.apply(from);
      }
    };
  }

  /**
   * Advances {@code iterator} {@code position + 1} times, returning the element at the {@code
   * position}th position.
   *
   * @param position position of the element to return
   * @return the element at the specified position in {@code iterator}

   * }
   *
   * refactored so that messageExpression is moved to a separate String-returning method.
   *
   * if (guardExpression) {
   *    throw new BadException(badMsg(...));
   * }
   *
   * The alternative natural refactorings into void or Exception-returning methods are much slower.
   * This is a big deal - we're talking factors of 2-8 in microbenchmarks, not just 10-20%. (This is

   * }
   *
   * refactored so that messageExpression is moved to a separate String-returning method.
   *
   * if (guardExpression) {
   *    throw new BadException(badMsg(...));
   * }
   *
   * The alternative natural refactorings into void or Exception-returning methods are much slower.
   * This is a big deal - we're talking factors of 2-8 in microbenchmarks, not just 10-20%. (This is

    assertThat(stats.loadExceptionCount()).isEqualTo(0);
    assertThat(stats.hitCount()).isEqualTo(2);

    key = new Object();
    assertThat(cache.get(key, Callables.returning(value))).isSameInstanceAs(value);
    stats = cache.stats();
    assertThat(stats.missCount()).isEqualTo(3);
    assertThat(stats.loadSuccessCount()).isEqualTo(4);
    assertThat(stats.loadExceptionCount()).isEqualTo(0);

    assertThat(stats.loadExceptionCount()).isEqualTo(0);
    assertThat(stats.hitCount()).isEqualTo(2);

    key = new Object();
    assertThat(cache.get(key, Callables.returning(value))).isSameInstanceAs(value);
    stats = cache.stats();
    assertThat(stats.missCount()).isEqualTo(3);
    assertThat(stats.loadSuccessCount()).isEqualTo(4);
    assertThat(stats.loadExceptionCount()).isEqualTo(0);

    assertNoExpectedFailures();
    super.tearDown();
  }

  public void testFrom() throws Exception {
    ClosingFuture<String> closingFuture =
        ClosingFuture.from(executor.submit(Callables.returning(closeable1)))
            .transform(
                (DeferredCloser closer, TestCloseable v) -> {
                  assertThat(v).isSameInstanceAs(closeable1);
                  return "value";
                },