class ActionDispatch::MiddlewareStack::Middleware

def initialize(klass_or_name, *args, &block)
  @klass = nil
  if klass_or_name.respond_to?(:name)
    @klass = klass_or_name
    @name  = @klass.name
  else
    @name  = klass_or_name.to_s
  end
  @classcache = ActiveSupport::Dependencies::Reference
  @args, @block = args, block
end