code: function fetch(records, chromosome, start, end) {
    // TODO(ihodes): Add sorted option to get O(lnN), fallback to O(N).
    return U.filter(records, function(record) {
      if (record.CHROM === chromosome && record.POS < end) {
        if (record.POS >= start)
          return true;
        if (record.INFO && record.INFO.END && record.INFO.END >= start)
          return true;
      }
      return false;
    });
  }
docs: Return list of records which fall between (or, in the case of a SNV, overlap)
  start and end.
  
  O(N) time.