def execute(username, password)
      logger.verbose("Making a WSTrust request with action #{@action}.")
      request = Net::HTTP::Get.new(@endpoint.path)
      add_headers(request)
      request.body = rst(username, password)
      response = http(@endpoint).request(request)
      if response.code == '200'
        WSTrustResponse.parse(response.body)
      else
        fail WSTrustResponse::WSTrustError, "Failed request: code #{response.code}."
      end
    end
def execute(username, password)
      logger.verbose("Making a WSTrust request with action #{@action}.")
      request = Net::HTTP::Get.new(@endpoint.path)
      add_headers(request)
      request.body = rst(username, password)
      response = http(@endpoint).request(request)
      if response.code == '200'
        WSTrustResponse.parse(response.body)
      else
        fail WSTrustResponse::WSTrustError, "Failed request: code #{response.code}."
      end
    end
Constructs a new WSTrustRequest.

 @param String|URI endpoint
 @param String action
 @param String applies_to

 Performs a WS-Trust RequestSecurityToken request with a username and
 password to obtain a federated token.

 @param String username
 @param String password
 @return WSTrustResponse