[HttpPost("VisualBasic")] // POST: /SyntaxTree/VisualBasic
        public async Task <SyntaxTreeNode> VisualBasicPost(CancellationToken cancellationToken)
        {
            using var reader = new StreamReader(Request.Body, Encoding.UTF8);
            string body = await reader.ReadToEndAsync().ConfigureAwait(false);

            SyntaxTree tree = VisualBasicSyntaxTree.ParseText(body);
            SyntaxNode root = await tree.GetRootAsync(cancellationToken).ConfigureAwait(false);

            Compilation    compilation = VisualBasicCompilation.Create("HelloWorld", new[] { tree });
            SemanticModel  model       = compilation.GetSemanticModel(tree);
            SyntaxTreeNode myRoot      = SyntaxTreeNode.CreateMyOwnTree(root, model);

            return(myRoot);
        }