   Configures strings used in the optional [server protocol](/up.protocol).
 
   @property up.protocol.config
+
   @param {string} [config.csrfHeader='X-CSRF-Token']
     The name of the HTTP header that will include the
     [CSRF token](https://en.wikipedia.org/wiki/Cross-site_request_forgery#Synchronizer_token_pattern)
     for AJAX requests.
+
   @param {string|Function(): string} [config.csrfParam]
     The `name` of the hidden `<input>` used for sending a
     [CSRF token](https://en.wikipedia.org/wiki/Cross-site_request_forgery#Synchronizer_token_pattern) when


    Defaults to the `content` attribute of a `<meta>` tag named `csrf-param`:

        <meta name="csrf-param" content="authenticity_token" />
  @param {string|Function(): string} [config.csrfToken]
    The [CSRF token](https://en.wikipedia.org/wiki/Cross-site_request_forgery#Synchronizer_token_pattern)
    to send for unsafe requests. The token will be sent as either a HTTP header (for AJAX requests)


    Defaults to the `content` attribute of a `<meta>` tag named `csrf-token`:

    ```
    <meta name='csrf-token' content='secret12345'>
    ```

  @param {string} [config.methodParam='_method']
    The name of request parameter containing the original request method when Unpoly needs to wrap
    the method.
