class WebSocket::Driver

def self.rack(socket, options = {})
  env     = socket.env
  version = env['HTTP_SEC_WEBSOCKET_VERSION']
  key     = env['HTTP_SEC_WEBSOCKET_KEY']
  key1    = env['HTTP_SEC_WEBSOCKET_KEY1']
  key2    = env['HTTP_SEC_WEBSOCKET_KEY2']
  if version or key
    Hybi.new(socket, options.merge(:require_masking => true))
  elsif key1 or key2
    Draft76.new(socket, options)
  else
    Draft75.new(socket, options)
  end
end