Method good

examples/Protonect.cpp:88–91

    level_ = Debug;
  }
  bool good()
  {
    return logfile_.is_open() && logfile_.good();
  }
  virtual void log(Level level, const std::string &message)
  {
    logfile_ << "[" << libfreenect2::Logger::level2str(level) << "] " << message << std::endl;