that are trusted to sign a server's certificate chain. `HandshakeCertificates` also works with
    mutual TLS where these roles are reversed.

    These classes make it possible to enable HTTPS in MockWebServer in [just a few lines of
    code][https_server_sample].

 *  **OkHttp now supports prior knowledge cleartext HTTP/2.** Enable this by setting
    `Protocol.H2_PRIOR_KNOWLEDGE` as the lone protocol on an `OkHttpClient.Builder`. This mode

            var date = cal.hasClass('left') ? this.leftCalendar.calendar[row][col] : this.rightCalendar.calendar[row][col];

            //
            // this function needs to do a few things:
            // * alternate between selecting a start and end date for the range,
            // * if the time picker is enabled, apply the hour/minute/second from the select boxes to the clicked date

    Iterable<?> a;
    Iterable<?> b;

    // Base case.
    a = new ArrayList<>();
    b = emptySet();
    assertTrue(elementsEqual(a.iterator(), b.iterator()));

    // A few elements.
    a = asList(4, 8, 15, 16, 23, 42);
    b = asList(4, 8, 15, 16, 23, 42);
    assertTrue(elementsEqual(a.iterator(), b.iterator()));

    // The same, but with nulls.

    Iterable<?> a;
    Iterable<?> b;

    // Base case.
    a = new ArrayList<>();
    b = emptySet();
    assertTrue(elementsEqual(a.iterator(), b.iterator()));

    // A few elements.
    a = asList(4, 8, 15, 16, 23, 42);
    b = asList(4, 8, 15, 16, 23, 42);
    assertTrue(elementsEqual(a.iterator(), b.iterator()));

    // The same, but with nulls.

   * <p>This implementation tries to be smart in a number of ways. It recognizes cases where the
   * negation is cheaper to precompute than the matcher itself; it tries to build small hash tables
   * for matchers that only match a few characters, and so on. In the worst-case scenario, it
   * constructs an eight-kilobyte bit array and queries that. In many situations this produces a
   * matcher which is faster to query than the original.
   */