private async Task <Document> GetChangedDocumentCoreAsync(CancellationToken cancellationToken)
 {
     if (_isQueryLocal)
     {
         return(await _service.IntroduceQueryLocalAsync(_document, _expression, _allOccurrences, cancellationToken).ConfigureAwait(false));
     }
     else if (_isLocal)
     {
         return(await _service.IntroduceLocalAsync(_document, _expression, _allOccurrences, _isConstant, cancellationToken).ConfigureAwait(false));
     }
     else
     {
         return(await IntroduceFieldAsync(cancellationToken).ConfigureAwait(false));
     }
 }