Better fix for unused size_result

Author: DefaultRyan

natvis/object_visualizer.cpp

@@ -612,7 +612,8 @@ std::wstring string_to_wstring(std::string_view const& str)
     }
 
     std::wstring result(size, L'?');
-    auto size_result = MultiByteToWideChar(CP_UTF8, 0, str.data(), static_cast<int>(str.size()), result.data(), size);
+    [[maybe_unused]] auto size_result = MultiByteToWideChar(CP_UTF8, 0, str.data(), static_cast<int>(str.size()), result.data(), size);
+    XLANG_ASSERT(size == size_result);
     return result;
 }