code: public boolean isWrapperFor(ServletResponse wrapped) {
          if (response == wrapped) {
              return true;
          } else if (response instanceof ServletResponseWrapper) {
              return ((ServletResponseWrapper) response).isWrapperFor(wrapped);
          } else {
              return false;
          }
      }
docs: Checks (recursively) if this ServletResponseWrapper wraps the given
  {@link ServletResponse} instance.
  
  @param wrapped the ServletResponse instance to search for
  
  @return true if this ServletResponseWrapper wraps the
  given ServletResponse instance, false otherwise
  
  @since Servlet 3.0