code: func (c *Iterator) NextRecord() (pilosa.Record, error) {
  	if ok := c.scanner.Scan(); ok {
  		c.line++
  		text := strings.TrimSpace(c.scanner.Text())
  		if text != "" {
  			rc, err := c.unmarshaller(text)
  			if err != nil {
  				return nil, fmt.Errorf("%s at line: %d", err.Error(), c.line)
  			}
  			return rc, nil
  		}
  	}
  	err := c.scanner.Err()
  	if err != nil {
  		return nil, err
  	}
  	return nil, io.EOF
  }
docs: // NextRecord iterates on lines of a Reader.
  // Returns io.EOF on end of iteration.