code: func NewGRPCLogger(config *Config, logger *log.Logger) *GRPCLogger {
  	return &GRPCLogger{
  		level: config.LogLevel,
  		l:     logger,
  	}
  }
docs: // NewGRPCLogger creates a grpclog.LoggerV2 that will output to the supplied
  // logger with Severity/Verbosity level appropriate for the given config.
  //
  // Note that grpclog has Info, Warning, Error, Fatal severity levels AND integer
  // verbosity levels for additional info. Verbose logs in glog are always INFO
  // severity so we map Info,V0 to INFO, Info,V1 to DEBUG, and Info,V>1 to TRACE.