original_string: protected function seedMiddlewareStack(callable $kernel = null)
      {
          if (!is_null($this->tip)) {
              throw new RuntimeException('MiddlewareStack can only be seeded once.');
          }
          if ($kernel === null) {
              $kernel = $this;
          }
          $this->tip = $kernel;
      }
code: protected function seedMiddlewareStack(callable $kernel = null)
      {
          if (!is_null($this->tip)) {
              throw new RuntimeException('MiddlewareStack can only be seeded once.');
          }
          if ($kernel === null) {
              $kernel = $this;
          }
          $this->tip = $kernel;
      }
code_tokens: protected function seedMiddlewareStack ( callable $ kernel = null ) { if ( ! is_null ( $ this -> tip ) ) { throw new RuntimeException ( 'MiddlewareStack can only be seeded once.' ) ; } if ( $ kernel === null ) { $ kernel = $ this ; } $ this -> tip = $ kernel ; }
docstring: Seed middleware stack with first callable
  
  @param callable $kernel The last item to run as middleware
  
  @throws RuntimeException if the stack is seeded more than once
docstring_tokens: Seed middleware stack with first callable