public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            if( reader.TokenType == JsonToken.Null )
            {
                return null;
            }

            if( reader.TokenType != JsonToken.StartObject )
            {
                var msg = string.Join(" ",
                    $"The JSON representation of binary data (byte[]) when parsing the server response is not a {Converter.PseudoTypeKey}:{Converter.Binary} object.",
                    $"This happens if your JSON document contains binary data (byte[]) in some other format (like a base64 string only) rather than a native RethinkDB pseudo type {Converter.PseudoTypeKey}:{Converter.Binary} object.",
                    $"If you are overriding the default Ser/Deserialization process, you need to make sure byte[] is a native {Converter.PseudoTypeKey}:{Converter.Binary} objects before using the built-in {nameof(ReqlBinaryConverter)}.",
                    "See https://rethinkdb.com/docs/data-types/ for more information about how binary data is represented in RethinkDB.");
                throw new JsonSerializationException(msg);
            }

            reader.ReadAndAssertProperty(Converter.PseudoTypeKey);
            var reql_type = reader.ReadAsString();
            if( reql_type != Converter.Binary )
            {
                throw new JsonSerializationException($"Expected {Converter.PseudoTypeKey} should be {Converter.Binary} but got {reql_type}.");
            }

            reader.ReadAndAssertProperty("data");

            var data = reader.ReadAsBytes();

            //realign and get out of the pseudo type
            //one more post read to align out of { reql_type:BINARY, data:""} 
            reader.ReadAndAssert();

            return data;
        }
        //EXAMPLE:
        // "r": [
        //    {
        //    "$reql_type$": "GROUPED_DATA",
        //    "data": [
        //        [
        //          "Alice",
        //          [
        //            { "id": 5,  "player": "Alice", "points": 7, "type": "free"},
        //            { "id": 12, "player": "Alice", "points": 2, "type": "free" }
        //          ]
        //        ],
        //        [
        //          "Bob",
        //          [
        //            { "id": 2,  "player": "Bob", "points": 15, "type": "ranked" },
        //            { "id": 11, "player": "Bob", "points": 10, "type": "free" }
        //          ]
        //        ]
        //       ]
        //    }
        // ]
        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            reader.ReadAndAssertProperty(Converter.PseudoTypeKey);
            var reql_type = reader.ReadAsString();
            if( reql_type != Converter.GroupedData )
            {
                throw new JsonSerializationException($"Expected {Converter.PseudoTypeKey} should be {Converter.GroupedData} but got {reql_type}.");
            }
            
            reader.ReadAndAssertProperty("data");

            //move reader to property value
            reader.ReadAndAssert();

            //... probably find a better way to do this.
            var listType = typeof(List<>).MakeGenericType(objectType);

            var list = (IList)Activator.CreateInstance(listType);

            var data = serializer.Deserialize<List<JArray>>(reader);
            foreach( var group in data )
            {
                var key = group[0]; //key, group value in common
                var items = group[1]; //the grouped items
                var grouping = Activator.CreateInstance(objectType, key, items);
                list.Add(grouping);
            }
            //.Select(arr => Activator.CreateInstance(objectType, arr) ).ToList();

            return list;
        }
        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            if( reader.TokenType == JsonToken.Null )
            {
                return null;
            }

            if( reader.TokenType != JsonToken.StartObject )
            {
                var msg = string.Join(" ",
                    $"The JSON representation of a DateTime/DateTimeOffset when parsing the server response is not a {Converter.PseudoTypeKey}:{Converter.Time} object.",
                    $"This happens if your JSON document contains DateTime/DateTimeOffsets in some other format (like an ISO8601 string) rather than a native RethinkDB pseudo type {Converter.PseudoTypeKey}:{Converter.Time} object.",
                    $"If you are overriding the default Ser/Deserialization process, you need to make sure DateTime/DateTimeOffset are native {Converter.PseudoTypeKey}:{Converter.Time} objects before using the built-in {nameof(ReqlDateTimeConverter)}.",
                    "See https://rethinkdb.com/docs/data-types/ for more information about how Date and Times are represented in RethinkDB.");
                throw new JsonSerializationException(msg);
            }

            reader.ReadAndAssertProperty(Converter.PseudoTypeKey);
            var reql_type = reader.ReadAsString();
            if( reql_type != Converter.Time )
            {
                throw new JsonSerializationException($"Expected {Converter.PseudoTypeKey} should be {Converter.Time} but got {reql_type}.");
            }

            reader.ReadAndAssertProperty("epoch_time");
            var epoch_time = reader.ReadAsDouble();
            if( epoch_time == null )
            {
                throw new JsonSerializationException($"The {Converter.PseudoTypeKey}:{Converter.Time} object doesn't have an epoch_time value.");
            }

            reader.ReadAndAssertProperty("timezone");
            var timezone = reader.ReadAsString();

            //realign and get out of the pseudo type
            //one more post read to align out of { reql_type:TIME,  .... } 
            reader.ReadAndAssert();

            if( objectType == typeof(DateTimeOffset) ||
                objectType == typeof(DateTimeOffset?) )
            {
                return ConvertDateTimeOffset(epoch_time.Value, timezone);
            }
            else
            {
                return ConvertDateTime(epoch_time.Value, timezone, serializer.DateTimeZoneHandling);
            }
        }
        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            if( reader.TokenType != JsonToken.StartObject )
            {
                var msg = string.Join(" ",
                    $"The JSON representation of a DateTime/DateTimeOffset when parsing the server response is not a {Converter.PseudoTypeKey}:{Converter.Time} object.",
                    $"This happens if your JSON document contains DateTime/DateTimeOffsets in some other format (like an ISO8601 string) rather than a native RethinkDB pseudo type {Converter.PseudoTypeKey}:{Converter.Time} object.",
                    $"If you are overriding the default Ser/Deserialization process, you need to make sure DateTime/DateTimeOffset are native {Converter.PseudoTypeKey}:{Converter.Time} objects before using the built-in {nameof(ReqlDateTimeConverter)}.",
                    "See https://rethinkdb.com/docs/data-types/ for more information about how Date and Times are represented in RethinkDB.");
                throw new JsonSerializationException(msg);
            }
            
            reader.ReadAndAssertProperty(Converter.PseudoTypeKey);
            var reql_type = reader.ReadAsString();
            if( reql_type != Converter.Time )
            {
                throw new JsonSerializationException($"Expected {Converter.PseudoTypeKey} should be {Converter.Time} but got {reql_type}.");
            }

            reader.ReadAndAssertProperty("epoch_time");
            var epoch_time = reader.ReadAsDecimal();
            if( epoch_time == null )
            {
                throw new JsonSerializationException($"The {Converter.PseudoTypeKey}:{Converter.Time} object doesn't have an epoch_time value.");
            }

            reader.ReadAndAssertProperty("timezone");
            var timezone = reader.ReadAsString();

            //realign and get out of the pseudo type
            //one more post read to align out of { reql_type:TIME,  .... } 
            reader.ReadAndAssert();

            var tz = TimeSpan.Parse(timezone.Substring(1));
            if( !timezone.StartsWith("+") )
                tz = -tz;

            var epoch = new DateTimeOffset(1970, 1, 1, 0, 0, 0, TimeSpan.Zero);
            var dt = epoch + TimeSpan.FromSeconds(Convert.ToDouble(epoch_time.Value));

            var dto = dt.ToOffset(tz);

            if( objectType == typeof(DateTimeOffset) )
                return dto;

            var tzHandle = serializer.DateTimeZoneHandling;

            switch( tzHandle )
            {
                case DateTimeZoneHandling.Local:
                    return dto.LocalDateTime;
                case DateTimeZoneHandling.Utc:
                    return dto.UtcDateTime;
                case DateTimeZoneHandling.Unspecified:
                    return dto.DateTime;
                case DateTimeZoneHandling.RoundtripKind:
                    return dto.Offset == TimeSpan.Zero ? dto.UtcDateTime : dto.LocalDateTime;
                default:
                    throw new JsonSerializationException("Invalid date time handling value.");
            }
        }