code: @SuppressWarnings({"UnusedDeclaration"})
      protected final void addFilterChain(String pattern, Key<? extends Filter>... keys) {
          filterChains.put(pattern, keys);
      }
docs: Adds a filter chain to the shiro configuration.
  <p/>
  NOTE: If the provided key is for a subclass of {@link org.apache.shiro.web.filter.PathMatchingFilter}, it will be registered with a proper
  provider.
  
  @param pattern
  @param keys