artifacted playback using `NAudio` with multiple raw pcm streams

public class NAudioPlayer : IPlayer
{
    private readonly ConcurrentDictionary<uint, BufferedWaveProvider> _waveProviders = new();
    private readonly MixingSampleProvider _mixer;
    private readonly WaveOutEvent _waveOut;
    private readonly WaveFormat _format = new(48000, 16, 2);

    public NAudioPlayer()
    {
        _mixer = new MixingSampleProvider(WaveFormat.CreateIeeeFloatWaveFormat(48000, 2));
        _mixer.ReadFully = true;
        _waveOut = new WaveOutEvent();
        _waveOut.Init(_mixer);
        _waveOut.Play();
    }

    public void AddSamples(byte[] pcmData, int pcmLength, uint ssrc)
    {
        if (!_waveProviders.TryGetValue(ssrc, out var waveProvider))
        {
            waveProvider = new BufferedWaveProvider(_format)
            {
                DiscardOnBufferOverflow = true
            };
            var sampleProvider = waveProvider.ToSampleProvider();
            _waveProviders.TryAdd(ssrc, waveProvider);
            _mixer.AddMixerInput(sampleProvider);
        }

        _waveProviders[ssrc].AddSamples(pcmData, 0, pcmLength);
    }
}