Betrachten wir es also aus dieser vereinfachten Sicht:

* Der Benutzer gibt den `username` und das `password` im Frontend ein und drückt `Enter`.
* Das Frontend (das im Browser des Benutzers läuft) sendet diesen `username` und das `password` an eine bestimmte URL in unserer API (deklariert mit `tokenUrl="token"`).

 * if (forceCacheResponse.code() != 504) {
 *   // The resource was cached! Show it.
 * } else {
 *   // The resource was not cached.
 * }
 * ```
 *
 * This technique works even better in situations where a stale response is better than no response.
 * To permit stale cached responses, use the `max-stale` directive with the maximum staleness in
 * seconds:
 *
 * ```java
 * Request request = new Request.Builder()

If you are paying for 3 servers but you are using only a little bit of their RAM and CPU, you are probably **wasting money** 💸, and probably **wasting server electric power** 🌎, etc.

In that case, it could be better to have only 2 servers and use a higher percentage of their resources (CPU, memory, disk, network bandwidth, etc).

  public void testFutureBash() {
    if (isWindows()) {
      return; // TODO: b/136041958 - Running very slowly on Windows CI.
    }
    CyclicBarrier barrier =
        new CyclicBarrier(
            6 // for the setter threads
                + 50 // for the listeners
                + 50 // for the blocking get threads,
                + 1); // for the main thread
    ExecutorService executor = newFixedThreadPool(barrier.getParties());

 * one can get a better result, as only a few registry suffixes are addressable. However, the most
 * useful test to determine if a domain is a plausible web host is {@link #hasPublicSuffix()}. This
 * will return {@code true} for many domains which (currently) are not hosts, such as {@code "com"},
 * but given that any public suffix may become a host without warning, it is better to err on the

        CipherSuite.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256,
        // Note that the following cipher suites are all on HTTP/2's bad cipher suites list. We'll
        // continue to include them until better suites are commonly available.
        CipherSuite.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
        CipherSuite.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
        CipherSuite.TLS_RSA_WITH_AES_128_GCM_SHA256,

           * A Throwable is very unlikely, but we really don't want to throw from a Suppressor, so
           * we catch everything. (Any Exception is either a RuntimeException or
           * sneaky checked exception.) With no better options, we log anything to the same
           * place as Closeables logs.
           */
          Closeables.logger.log(
              Level.WARNING, "Suppressing exception thrown when closing " + closeable, suppressed);

     * @return the home directory path
     */
    public String getHomeDirectory() {
        return this.homeDirectory;
    }

    /**
     * Returns the user's home drive letter.
     * @return the home drive
     */
    public String getHomeDrive() {
        return this.homeDrive;
    }

    /**
     * Returns the name of the server that authenticated the user.

            throws SmbException {
        if (host.indexOf('.') < 0 && host.toUpperCase(Locale.ROOT).equals(host)) {
            // this is not too good, probably should better pass the address and check that it is a netbios one.
            // While we could look up the domain controller/KDC we cannot really make the java kerberos implementation
            // use a KDC of our choice.

Pero en este caso, la misma aplicación de **FastAPI** manejará la API y la autenticación.

Así que, revisémoslo desde ese punto de vista simplificado:

* El usuario escribe el `username` y `password` en el frontend, y presiona `Enter`.
* El frontend (ejecutándose en el navegador del usuario) envía ese `username` y `password` a una URL específica en nuestra API (declarada con `tokenUrl="token"`).