Currently, the [rack.rb](https://github.com/elct9620/hanami-lambda/blob/8592279e22df1f79448360cdda12d439a3b9dae1/lib/hanami/lambda/rack.rb) only implements minimal Rack interface. We can reference [Lamby](https://github.com/rails-lambda/lamby) to implement more functions for Rack support.
