Claim's JsonConverter for System.Text.Json

ClaimJsonConverter.cs

using System.Security.Claims;
using System.Text.Json;
using System.Text.Json.Serialization;

namespace System.Security.Claims.Serialization;

public class ClaimJsonConverter : JsonConverter<Claim>
{
    // Supported properties:
    private const string Issuer = "Issuer";
    private const string OriginalIssuer = "OriginalIssuer";
    private const string Type = "Type";
    private const string Value = "Value";
    private const string ValueType = "ValueType";

    public static readonly ClaimJsonConverter Instance = new();

    public override Claim Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
    {
        if (reader.TokenType != JsonTokenType.StartObject)
            throw new JsonException("Expected start of data");

        string? issuer = null;
        string? originalIssuer = null;
        string? type = null;
        string? value = null;
        string? valueType = null;

        while (reader.Read())
        {
            if (reader.TokenType == JsonTokenType.EndObject)
            {
                if (type is null)
                    throw new JsonException($"Missing property: {Type}");

                if (value is null)
                    throw new JsonException($"Missing property: {Value}");

                return new Claim(type, value, valueType, issuer, originalIssuer);
            }

            if (reader.TokenType == JsonTokenType.PropertyName)
            {
                var propertyName = reader.GetString();
                reader.Read();

                switch (propertyName)
                {
                    case Issuer:
                        issuer = reader.GetString();
                        break;
                    case OriginalIssuer:
                        originalIssuer = reader.GetString();
                        break;
                    case Type:
                        type = reader.GetString();
                        break;
                    case Value:
                        value = reader.GetString();
                        break;
                    case ValueType:
                        valueType = reader.GetString();
                        break;
                    default:
                        throw new JsonException($"Unexpected property: {propertyName}");

                }
            }
        }

        throw new JsonException("Unexpected end of data");
    }

    public override void Write(Utf8JsonWriter writer, Claim value, JsonSerializerOptions options)
    {
        writer.WriteStartObject();
        writer.WriteString(Issuer, value.Issuer);
        writer.WriteString(OriginalIssuer, value.OriginalIssuer);
        writer.WriteString(Type, value.Type);
        writer.WriteString(Value, value.Value);
        writer.WriteString(ValueType, value.ValueType);
        writer.WriteEndObject();
    }
}

Using:

        const string json = @"{
            ""Type"": ""sub"",
            ""Value"": ""1234567890"",
            ""ValueType"": ""http://www.w3.org/2001/XMLSchema#string"",
            ""Issuer"": ""Issuer"",
            ""OriginalIssuer"": ""OriginalIssuer""
        }";

        var options = new JsonSerializerOptions();
        options.Converters.Add(ClaimJsonConverter.Instance);

        var claim = JsonSerializer.Deserialize<Claim>(json, options);