code: func (c *DefaultIndexingChain) fillStoredFields(docId int) (err error) {
  	for err == nil && c.lastStoredDocId < docId {
  		err = c.startStoredFields()
  		if err == nil {
  			err = c.finishStoredFields()
  		}
  	}
  	return
  }
docs: /*
  Catch up for all docs before us that had no stored fields, or hit
  non-aborting errors before writing stored fields.
  */