[MemoryDiagnoser]
public unsafe class JsonStats
{
    private byte* _jsonBytesPtr;
    private int _jsonBytesLen;

    [GlobalSetup]
    public void GlobalSetup()
    {
        byte[] jsonBytes = File.ReadAllBytes("kafka.json");
        _jsonBytesPtr = (byte*)NativeMemory.Alloc((UIntPtr)jsonBytes.Length);
        _jsonBytesLen = jsonBytes.Length;
        jsonBytes.AsSpan().CopyTo(new Span<byte>(_jsonBytesPtr, _jsonBytesLen));
    }

    [GlobalCleanup]
    public void GlobalCleanup()
    {
        NativeMemory.Free(_jsonBytesPtr);
    }

    [Benchmark]
    public void Old()
    {
        string json = Encoding.UTF8.GetString(_jsonBytesPtr, _jsonBytesLen);
        using var doc = JsonSerializer.Deserialize<JsonDocument>(json);
    }

    [Benchmark]
    public void New()
    {
        ReadOnlySpan<byte> json = new(_jsonBytesPtr, _jsonBytesLen);
        using var doc = JsonSerializer.Deserialize<JsonDocument>(json);
    }
}