# File lib/ftw/agent.rb, line 189
  def upgrade!(uri, protocol, options={})
    req = request("GET", uri, options)
    req.headers["Connection"] = "Upgrade"
    req.headers["Upgrade"] = protocol
    response = execute(req)
    if response.status == 101
      # Success, return the response object and the connection to hand off.
      return response, response.body
    else
      return response, nil
    end
  end