The problem is that GWT responds poorly to two .gwt.xml files in the same
    Java package; see
    https://groups.google.com/g/google-web-toolkit-contributors/c/CqYH59Dt_rQ/m/uVGW1QdUsXUJ
    for details.

    The summary is that it ignores one file in favor of the other.
    util.concurrent, like nearly all our packages, has two .gwt.xml files: one

    The problem is that GWT responds poorly to two .gwt.xml files in the same
    Java package; see
    https://groups.google.com/g/google-web-toolkit-contributors/c/CqYH59Dt_rQ/m/uVGW1QdUsXUJ
    for details.

    The summary is that it ignores one file in favor of the other.
    util.concurrent, like nearly all our packages, has two .gwt.xml files: one

     *
     * @throws IllegalArgumentException if any two keys are equal according to the comparator (which
     *     might be the keys' natural order)
     */
    @Override
    public ImmutableSortedMap<K, V> build() {
      return buildOrThrow();
    }

    /**
     * Returns a newly-created immutable sorted map, or throws an exception if any two keys are
     * equal.
     *

    assertEquals(s2, three.next().target);
    assertEquals(o1, three.next().target);
    assertFalse(three.hasNext());

    Iterator<Subscriber> two = registry.getSubscribers("");
    assertEquals(s1, two.next().target);
    assertEquals(o1, two.next().target);
    assertFalse(two.hasNext());
  }

  public static class StringSubscriber {

    @Subscribe
    public void handle(String s) {}
  }

# Sub Applications - Mounts

If you need to have two independent FastAPI applications, with their own independent OpenAPI and their own docs UIs, you can have a main app and "mount" one (or more) sub-application(s).

## Mounting a **FastAPI** application

"Mounting" means adding a completely "independent" application in a specific path, that then takes care of handling everything under that path, with the _path operations_ declared in that sub-application.

object WebSocketProtocol {
  /** Magic value which must be appended to the key in a response header. */
  internal const val ACCEPT_MAGIC = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"

  /*
  Each frame starts with two bytes of data.

   0 1 2 3 4 5 6 7    0 1 2 3 4 5 6 7
  +-+-+-+-+-------+  +-+-------------+
  |F|R|R|R| OP    |  |M| LENGTH      |
  |I|S|S|S| CODE  |  |A|             |
  |N|V|V|V|       |  |S|             |

   * default rounding mode: if the two nearest representable values are equally near, the one with
   * the least significant bit zero is chosen. (In such cases, both of the nearest representable
   * values are even integers; this method returns the one that is a multiple of a greater power of
   * two.)
   *

    unfiltered.put("two", 2);
    unfiltered.put("three", 3);
    unfiltered.put("four", 4);
    assertEquals(ImmutableMap.of("two", 2, "three", 3, "four", 4), unfiltered);
    assertEquals(ImmutableMap.of("three", 3, "four", 4), filtered);

    unfiltered.remove("three");
    assertEquals(ImmutableMap.of("two", 2, "four", 4), unfiltered);
    assertEquals(ImmutableMap.of("four", 4), filtered);

            assert data == "Session cookie or query token value is: fakesession"
            data = websocket.receive_text()
            assert data == f"Message text was: {message}, for item ID: foo"
            message = "Message two"
            websocket.send_text(message)
            data = websocket.receive_text()
            assert data == "Session cookie or query token value is: fakesession"
            data = websocket.receive_text()

    assertMultimapEquals(ImmutableListMultimap.of("one", 1, "two", 2), "one", 1, "two", 2);
    assertMultimapEquals(
        ImmutableListMultimap.of("one", 1, "two", 2, "three", 3), "one", 1, "two", 2, "three", 3);
    assertMultimapEquals(
        ImmutableListMultimap.of("one", 1, "two", 2, "three", 3, "four", 4),
        "one",
        1,
        "two",
        2,
        "three",
        3,
        "four",