Deserializing JSON Lines test

DeserializeJsonLines.cs

using System;
using System.IO;
using System.Text;
using System.Text.Json;

// need System.Text.Json 9.0 or later

namespace jsonserializertest
{
    class Program
    {
        record struct JsonLineValue(string A, int B);
        static string GenerateJsonLines()
        {
            var sb = new StringBuilder();
            {
                using var sw = new StringWriter(sb);
                for(int i = 0;i<10;i++)
                {
                    var str = JsonSerializer.Serialize(new JsonLineValue($"a{i}", i));
                    sw.WriteLine(str);
                }
            }
            return sb.ToString();
        }
        static void JsonLinesTest()
        {
            var str = GenerateJsonLines();
            Console.WriteLine($"generated string is '{str}'");
            var utf8 = Encoding.UTF8.GetBytes(str);
            var jr = new Utf8JsonReader(utf8, new JsonReaderOptions(){ AllowMultipleValues = true });
            // Unhandled exception. System.Text.Json.JsonException: The JSON value could not be converted to jsonserializertest.Program+JsonLineValue[]. Path: $ | LineNumber: 0 | BytePositionInLine: 1.
            // foreach(var item in JsonSerializer.Deserialize<JsonLineValue[]>(ref jr))
            // {
            //     Console.WriteLine(item);
            // }

            while(jr.Read())
            {
                if(jr.TokenType == JsonTokenType.StartObject)
                {
                    var val = JsonSerializer.Deserialize<JsonLineValue>(ref jr);
                    Console.WriteLine(val.ToString());
                }
            }
        }
        static void Main(string[] args)
        {
            JsonLinesTest();
        }
    }
}