code: func mysqlConnStr(cfg migrateConfig) string {
  	var out bytes.Buffer
  
  	out.WriteString(cfg.User)
  	if len(cfg.Pass) > 0 {
  		out.WriteByte(':')
  		out.WriteString(cfg.Pass)
  	}
  	out.WriteString(fmt.Sprintf("@tcp(%s:%d)/%s", cfg.Host, cfg.Port, cfg.DBName))
  	if len(cfg.SSLMode) > 0 {
  		out.WriteString("?tls=")
  		out.WriteString(cfg.SSLMode)
  	}
  
  	return out.String()
  }
docs: // mysqlConnStr returns a mysql connection string compatible with the
  // Go mysql driver package, in the format:
  // user:pass@tcp(host:port)/dbname?tls=true