code: func NewIngester(source Source, parser RecordParser, mapper RecordMapper, indexer Indexer) *Ingester {
  	return &Ingester{
  		ParseConcurrency: 1,
  
  		src:     source,
  		parser:  parser,
  		mapper:  mapper,
  		indexer: indexer,
  
  		// Reasonable defaults for crosscutting dependencies.
  		Stats: termstat.NewCollector(os.Stdout),
  		Log:   StdLogger{log.New(os.Stderr, "Ingest", log.LstdFlags)},
  	}
  }
docs: // NewIngester gets a new Ingester.