public TagKeyValueMapConverter(boolean nullIfEmpty,String idKey){
  Objects.requireNonNull(idKey);
  this.nullIfEmpty=nullIfEmpty;
  this.addId=true;
  this.idKey=idKey;
}

public TagKeyValueMapConverter ( boolean nullIfEmpty , String idKey ) { Objects . requireNonNull ( idKey ) ; this . nullIfEmpty = nullIfEmpty ; this . addId = true ; this . idKey = idKey ; }
store feature ids using idkey . id value may be null if not present .
