Represents an unordered collection of EmberType instances.
There's usually exactly one singleton EmberTypeBag instance for each DTD, see e.g. Glow.GlowTypes.
        /// <summary>Initializes a new instance of the <see cref="EmberConverter"/> class.</summary>
        /// <param name="types">A collection of <see cref="EmberType"/> instances to base the XML conversion on.</param>
        /// <exception cref="ArgumentNullException"><paramref name="types"/> equals <c>null</c>.</exception>
        public EmberConverter(EmberTypeBag types)
        {
            if (types == null)
            {
                throw new ArgumentNullException(nameof(types));
            }

            this.typeNames    = types.TypeNames;
            this.fieldNames   = types.FieldNames;
            this.innerNumbers = types.InnerNumbers;
            this.fieldIds     = types.FieldIds;
        }