preserveObjectReferences causes serialization of large objects to hang

[shivanan]

When trying to serialize a large object, setting preserveObjectReferences to true causes the serialization to hang indefinitely.
I've only noticed this behavior with large objects.

I guess its perfectly fine to turn off that option, but thought I'd report it anyway as it seems strange.

Reproducible in both Wire and Hyperion and on .NET Core 2.1 and .NET Framework 4.6

static void Main(string[] args)
        {
            Hyperion.Serializer s = new Hyperion.Serializer(new Hyperion.SerializerOptions(preserveObjectReferences:true));
            var obj = new List<Dictionary<string, object>>();
            for (var i = 0; i < 1000000;i++)
            {
                var item = new Dictionary<string, object>();
                item["x"] = i;
                item["y"] = DateTime.Now;
                obj.Add(item);
            }
            var dict = new Dictionary<string, object>();
            dict["key"] = obj;

            using (var ms = new System.IO.MemoryStream())
            {
                s.Serialize(dict, ms);
                Console.WriteLine("Serialized Size: {0}", ms.Length);
            }


        }