XmlSerializer Cache Class

XmlSerializerCache.cs

// Based on https://codereview.stackexchange.com/questions/24861/caching-xmlserializer-in-appdomain
public static class XmlSerializerCache
{
    private AppDomain cache {
        get {
            return AppDomain.CurrentDomain;
        }
    }
    public static XmlSerializer GetXmlSerializer(Type type, XmlRootAttribute xmlRoot)
    {
        var key = String.Format(CultureInfo.InvariantCulture, "CachedXmlSerializer:{0}:{1}", type, xmlRoot.ElementName);

        var serializer = cache.GetData(key) as XmlSerializer;
        if (serializer == null)
        {
            serializer = new XmlSerializer(type, xmlRoot);
            cache.SetData(key, serializer);
        }
        return serializer;
    }
    public static XmlSerializer GetXmlSerializer(Type type)
    {
        var key = String.Format(CultureInfo.InvariantCulture, "CachedXmlSerializer:{0}", type);

        var serializer = cache.GetData(key) as XmlSerializer;
        if (serializer == null)
        {
            serializer = new XmlSerializer(type);
            cache.SetData(key, serializer);
        }
        return serializer;
    }
}