internal async Task <(DocumentSnapshot primary, Document generatedDocument, TextSpan generatedSpan)> InitializeWithSnapshotAsync(string razorSource)
        {
            var(razorSourceText, primarySpan) = CreateText(razorSource);
            var(primary, generatedDocument)   = InitializeDocument(razorSourceText);
            var generatedSpan = await DocumentExcerptServiceTestBase.GetSecondarySpanAsync(primary, primarySpan, generatedDocument);

            return(primary, generatedDocument, generatedSpan);
        }
        public async Task <(Document generatedDocument, SourceText razorSourceText, TextSpan primarySpan, TextSpan generatedSpan)> InitializeAsync(string razorSource)
        {
            var(razorSourceText, primarySpan) = CreateText(razorSource);
            var(primary, generatedDocument)   = InitializeDocument(razorSourceText);
            var generatedSpan = await DocumentExcerptServiceTestBase.GetSecondarySpanAsync(primary, primarySpan, generatedDocument);

            return(generatedDocument, razorSourceText, primarySpan, generatedSpan);
        }