private async Task <Document> InjectInstance(Document document, ClassDeclarationSyntax classNode, SimpleNameSyntax typeName)
{
var fieldName = "_" + ToVariableName(typeName);
var fieldIdentifier = SyntaxFactory.Identifier(fieldName);
ClassDeclarationSyntax updatedClass = classNode;
var typeNameStr = typeName.GetText().ToString();
updatedClass = updatedClass.ReplaceNode(typeName, SyntaxFactory.IdentifierName(fieldName));
updatedClass = InjectToConstructor(typeName, updatedClass, fieldIdentifier);
var root = await document.GetSyntaxRootAsync();
root = root.ReplaceNode(classNode, updatedClass);
return(document.WithSyntaxRoot(root));
}