return Collections.singleton(reference);
  }

  @Override
  public <V> Optional<V> transform(Function<? super T, V> function) {
    return new Present<>(
        checkNotNull(
            function.apply(reference),
            "the Function passed to Optional.transform() must not return null."));
  }

  @Override
  public boolean equals(@Nullable Object obj) {
    if (obj instanceof Present) {

    File asciiFile = getTestFile("ascii.txt");
    File dir = asciiFile.getParentFile();
    assertTrue(Files.isDirectory().apply(dir));
    assertFalse(Files.isFile().apply(dir));

    assertFalse(Files.isDirectory().apply(asciiFile));
    assertTrue(Files.isFile().apply(asciiFile));
  }

  /** Returns a root path for the file system. */
  private static File root() {
    return File.listRoots()[0];
  }

    Iterator<String> filtered =
        filter(
            unfiltered,
            new Predicate<String>() {
              @Override
              public boolean apply(String s) {
                throw new AssertionFailedError("Should never be evaluated");
              }
            });

    List<String> expected = emptyList();

          transform(
              asList(parameters),
              new Function<TypeVariable<?>, TypeParameterSignature>() {
                @Override
                public TypeParameterSignature apply(TypeVariable<?> from) {
                  return new TypeParameterSignature(from);
                }
              });
    }

    @Override
    public boolean equals(@Nullable Object obj) {

          transform(
              asList(parameters),
              new Function<TypeVariable<?>, TypeParameterSignature>() {
                @Override
                public TypeParameterSignature apply(TypeVariable<?> from) {
                  return new TypeParameterSignature(from);
                }
              });
    }

    @Override
    public boolean equals(@Nullable Object obj) {

    // request headers.
    // 431 "Request Header Fields Too Large"
    val largeHeaders =
      Headers
        .Builder()
        .apply {
          repeat(32) {
            add("name-$it", "value-$it-" + "0".repeat(1024))
          }
        }.build()
    val call2 =
      client.newCall(
        Request
          .Builder()

    DelayingIdentityLoader(CountDownLatch delayLatch) {
      this.delayLatch = delayLatch;
    }

    @CanIgnoreReturnValue // Sure, why not?
    @Override
    public T apply(T key) {
      awaitUninterruptibly(delayLatch);
      return key;
    }
  }

  /*
   * TODO(cpovirk): eliminate duplication between these tests and those in LegacyMapMakerTests and
   * anywhere else
   */

        super(true);
        this.root = root;
    }

    /**
     * <p>Split the expression into parts, tokenized on the dot ('.') character. Then,
     * starting at the root object contained in this value source, apply each part
     * to the object graph below this root, using either 'getXXX()' or 'isXXX()'
     * accessor types to resolve the value for each successive expression part.

        return this;
    }

    /**
     * Applies another function to this Ansi instance.
     *
     * @param fun the function to apply
     * @return this Ansi instance
     * @since 2.2
     */
    public Ansi apply(Consumer fun) {
        fun.apply(this);
        return this;
    }

    /**
     * Uses the {@link org.jline.jansi.AnsiRenderer}

    val accepted: List<ReportMessage>
) {

    val isEmpty: Boolean
        get() = errors.isEmpty() && warnings.isEmpty() && information.isEmpty()

    fun toText() =
        StringBuilder("Binary compatibility\n").apply {
            listOf("Errors" to errors, "Warnings" to warnings, "Information" to information, "Accepted" to accepted).forEach { (name, list) ->
                if (list.isNotEmpty()) {