code: func filterRecordsForPlan(records []*endpoint.Endpoint) []*endpoint.Endpoint {
  	filtered := []*endpoint.Endpoint{}
  
  	for _, record := range records {
  		// Explicitly specify which records we want to use for planning.
  		// TODO: Add AAAA records as well when they are supported.
  		switch record.RecordType {
  		case endpoint.RecordTypeA, endpoint.RecordTypeCNAME:
  			filtered = append(filtered, record)
  		default:
  			continue
  		}
  	}
  
  	return filtered
  }
docs: // filterRecordsForPlan removes records that are not relevant to the planner.
  // Currently this just removes TXT records to prevent them from being
  // deleted erroneously by the planner (only the TXT registry should do this.)
  //
  // Per RFC 1034, CNAME records conflict with all other records - it is the
  // only record with this property. The behavior of the planner may need to be
  // made more sophisticated to codify this.