handle_open

# File actioncable/lib/action_cable/connection/base.rb, line 165
        def handle_open
          @protocol = websocket.protocol
          connect if respond_to?(:connect)
          subscribe_to_internal_channel
          send_welcome_message

          message_buffer.process!
          server.add_connection(self)
        rescue ActionCable::Connection::Authorization::UnauthorizedError
          respond_to_invalid_request
        end