private static FormsModel ReadData(JsonReader reader)
        {
            bool isPersistent;
            DateTimeOffset expireUtc;
            var principal = new ClaimsPrincipal();

            reader
                .StartObject()
                .Property("p", out isPersistent, true)
                .Property("e", out expireUtc, DateTimeOffset.MinValue)
                .StartArray("i");

            while (reader.TokenType != JsonToken.EndArray)
            {
                string authenticationType;
                string nameClaimType;
                string roleClaimType;
                var claims = new List<Claim>();

                reader
                    .StartObject()
                    .Property("at", out authenticationType, null)
                    .Property("nct", out nameClaimType, ClaimsIdentity.DefaultNameClaimType)
                    .Property("rct", out roleClaimType, ClaimsIdentity.DefaultRoleClaimType)
                    .StartArray("c");

                while (reader.TokenType != JsonToken.EndArray)
                {
                    string claimType;
                    string claimValue;
                    reader
                        .StartObject()
                        .Property("t", out claimType, nameClaimType)
                        .Property("v", out claimValue, null)
                        .EndObject();
                    claims.Add(new Claim(claimType, claimValue));
                }

                reader
                    .EndArray()
                    .EndObject();

                principal.AddIdentity(new ClaimsIdentity(
                    claims,
                    authenticationType,
                    nameClaimType,
                    roleClaimType));
            }

            reader
                .EndArray()
                .EndObject(final: true);

            return new FormsModel
            {
                IsPersistent = isPersistent,
                ExpireUtc = expireUtc,
                Principal = principal
            };
        }