private static string XSerializerJsonSerialize(JsonSerializer<Foo2> jsonSerializer, Foo2 foo)
 {
     var sb = new StringBuilder();
     using (var writer = new StringWriter(sb))
     {
         jsonSerializer.Serialize(writer, foo);
     }
     return sb.ToString();
 }
 private static string NewtonsoftJsonSerialize(Newtonsoft.Json.JsonSerializer jsonSerializer, Foo2 foo)
 {
     var sb = new StringBuilder();
     using (var writer = new StringWriter(sb))
     {
         jsonSerializer.Serialize(writer, foo);
     }
     return sb.ToString();
 }