*/
  public static final String KEEP_ALIVE = "Keep-Alive";
  /**
   * The HTTP <a href="https://github.com/WICG/nav-speculation/blob/main/no-vary-search.md">{@code
   * No-Vary-Seearch}</a> header field name.
   *
   * @since 32.0.0
   */
  public static final String NO_VARY_SEARCH = "No-Vary-Search";
  /**
   * The HTTP <a href="https://googlechrome.github.io/OriginTrials/#header">{@code Origin-Trial}</a>
   * header field name.

          println("Server: ${response.header("Server")}")
          println("Date: ${response.header("Date")}")
          println("Vary: ${response.headers("Vary")}")
        }
      }
    ```

=== ":material-language-java: Java"
    ```java
      private final OkHttpClient client = new OkHttpClient();

      public void run() throws Exception {

  @CheckForNull
  V forcePut(@ParametricNullness K key, @ParametricNullness V value);

  // Bulk Operations

  /**
   * {@inheritDoc}
   *
   * <p><b>Warning:</b> the results of calling this method may vary depending on the iteration order
   * of {@code map}.
   *
   * @throws IllegalArgumentException if an attempt to {@code put} any entry fails. Note that some

    cacheHit.cacheResponse()
      .assertCode(200)
      .assertHeader("Donut", "a")
      .assertHeader("ETag", "v1")
      .assertRequestUrl(server.url("/"))
      .assertRequestHeader("Accept-Language") // No Vary on Accept-Language.
      .assertRequestHeader("Accept-Charset", "UTF-8") // Because of Vary on Accept-Charset.

  @CheckForNull
  V forcePut(@ParametricNullness K key, @ParametricNullness V value);

  // Bulk Operations

  /**
   * {@inheritDoc}
   *
   * <p><b>Warning:</b> the results of calling this method may vary depending on the iteration order
   * of {@code map}.
   *
   * @throws IllegalArgumentException if an attempt to {@code put} any entry fails. Note that some

  resolved "https://registry.yarnpkg.com/utils-merge/-/utils-merge-1.0.1.tgz#9f95710f50a267947b2ccc124741c1028427e713"
  integrity sha1-n5VxD1CiZ5R7LMwSR0HBAoQn5xM=

vary@^1:
  version "1.1.2"
  resolved "https://registry.yarnpkg.com/vary/-/vary-1.1.2.tgz#2299f02c6ded30d4a5961b0b9f74524a18f634fc"
  integrity sha1-IpnwLG3tMNSllhsLn3RSShj2NPw=

void-elements@^2.0.0:
  version "2.0.1"

	{nil, []byte(""), 0},
	{[]byte("a"), nil, 1},
	{nil, []byte("a"), -1},
}

func TestCompare(t *testing.T) {
	for _, tt := range compareTests {
		numShifts := 16
		buffer := make([]byte, len(tt.b)+numShifts)
		// vary the input alignment of tt.b
		for offset := 0; offset <= numShifts; offset++ {
			shiftedB := buffer[offset : len(tt.b)+offset]
			copy(shiftedB, tt.b)
			cmp := Compare(tt.a, shiftedB)
			if cmp != tt.i {

## Documenting the callback

The actual callback code will depend heavily on your own API app.

And it will probably vary a lot from one app to the next.

It could be just one or two lines of code, like:

```Python
callback_url = "https://example.com/api/v1/invoices/events/"

        // this relies heavily on the equals() and hashCode() for ComponentDescriptor,
        // which uses role:roleHint for identity...and roleHint == goalPrefix:goal.
        // role does not vary for Mojos.
        List<MojoDescriptor> mojos = getMojos();

        if (mojos != null && mojos.contains(mojoDescriptor)) {
            int indexOf = mojos.indexOf(mojoDescriptor);

    private const val UNICODE_4 = 0x1d11e

    /**
     * Returns a new instance configured with a default encode set for the ASCII range. The specific
     * rules vary per-component: for example, '?' may be identity-encoded in a fragment, but must be
     * percent-encoded in a path.
     *
     * See https://url.spec.whatwg.org/#percent-encoded-bytes
     */