code: @Nonnull
    public final UnifiedResponse setStatusUnauthorized (@Nullable final String sAuthenticate)
    {
      _setStatus (HttpServletResponse.SC_UNAUTHORIZED);
      if (StringHelper.hasText (sAuthenticate))
        m_aResponseHeaderMap.setHeader (CHttpHeader.WWW_AUTHENTICATE, sAuthenticate);
      return this;
    }
docs: Special handling for returning status code 401 UNAUTHORIZED.
  
  @param sAuthenticate
  The string to be used for the {@link CHttpHeader#WWW_AUTHENTICATE}
  response header. May be <code>null</code> or empty.
  @return this