* [proxyAuthenticator] to set the authenticator for proxy servers.
     *
     * If unset, the [no authentication will be attempted][Authenticator.NONE].
     */
    fun authenticator(authenticator: Authenticator) =
      apply {
        this.authenticator = authenticator
      }

    /** Configure this client to follow redirects. If unset, redirects will be followed. */
    fun followRedirects(followRedirects: Boolean) =

    }

    @Override
    public Object getValue() {
      throw new AssertionError();
    }
  }

  /**
   * A singleton {@link WeakValueReference} used to denote an unset value in an entry with weak
   * values.
   */
  static final WeakValueReference<Object, Object, DummyInternalEntry> UNSET_WEAK_VALUE_REFERENCE =
      new WeakValueReference<Object, Object, DummyInternalEntry>() {

    }

    @Override
    public Object getValue() {
      throw new AssertionError();
    }
  }

  /**
   * A singleton {@link WeakValueReference} used to denote an unset value in an entry with weak
   * values.
   */
  static final WeakValueReference<Object, Object, DummyInternalEntry> UNSET_WEAK_VALUE_REFERENCE =
      new WeakValueReference<Object, Object, DummyInternalEntry>() {

    val result = Builder()
    result.scheme = scheme
    result.encodedUsername = encodedUsername
    result.encodedPassword = encodedPassword
    result.host = host
    // If we're set to a default port, unset it in case of a scheme change.
    result.port = if (port != defaultPort(scheme)) port else -1
    result.encodedPathSegments.clear()
    result.encodedPathSegments.addAll(encodedPathSegments)