code: func NewMain() *Main {
  	m := &Main{
  		Concurrency:      1,
  		FetchConcurrency: 1,
  		Index:            "taxi",
  		nexter:           pdk.NewNexter(),
  		urls:             make([]string, 0),
  
  		totalRecs:     &counter{},
  		skippedRecs:   &counter{},
  		nullLocs:      &counter{},
  		badLocs:       &counter{},
  		badSpeeds:     &counter{},
  		badTotalAmnts: &counter{},
  		badDurations:  &counter{},
  		badPassCounts: &counter{},
  		badDist:       &counter{},
  		badUnknowns:   &counter{},
  	}
  
  	return m
  }
docs: // NewMain returns a new instance of Main with default values.