code: function () {
      insertCfg.model.sync({force: true}).then(function () {
        var streamInserterCfg = util.makeStreamerConfig(insertCfg.model)
        var inserter = dbStreamer.getInserter(streamInserterCfg)
  
        inserter.connect(function (err) {
          if (err) return callback(err)
          csv()
            .fromFile(insertCfg.filename)
            .on('json', line => {
              inserter.push(transformer2(line))
            })
            .on('done', err => {
              if (err) return callback(err)
              inserter.setEndHandler(callback)
              inserter.end()
            })
        })
      })
    }
docs: prepare processing function, but don't run it until file existance is confirmed