code: func SendAppLog(appID, message, sourceType, sourceInstance string) error {
  	if logSender == nil {
  		return nil
  	}
  	return logSender.SendAppLog(appID, message, sourceType, sourceInstance)
  }
docs: // SendAppLog sends a log message with the given appid, log message, source type
  // and source instance, with a message type of std out.
  // Returns an error if one occurs while sending the event.