code: func AddFields(ctx context.Context, fields logrus.Fields) {
  	l, ok := ctx.Value(ctxLoggerKey).(*ctxLogger)
  	if !ok || l == nil {
  		return
  	}
  	for k, v := range fields {
  		l.fields[k] = v
  	}
  }
docs: // AddFields adds logrus fields to the logger.