Sound does not play in 'OpenTK.OpenAL 4.x'

I am upgrading from OpenTK 3.3.3 to OpenTK 4.7.7.

The migrated code below doesn't work.
(There are no errors, no sound.)

		//OpenTK.OpenAL 4.7.7
		var device = ALC.OpenDevice(null);
		var context = ALC.CreateContext(device, new ALContextAttributes());
		ALC.MakeContextCurrent(context);

		int bufferId = AL.GenBuffer();
		int sourceId = AL.GenSource();

		int channels, bits_per_sample, sample_rate;
		byte[] soundData = LoadWave(
			File.Open(sFileName, FileMode.Open),
			out channels,
			out bits_per_sample,
			out sample_rate);
		AL.BufferData(bufferId
			, GetSoundFormat(channels, bits_per_sample)
			, soundData
			, bits_per_sample);

		AL.Source(sourceId, ALSourcei.Buffer, bufferId);
		AL.Source(sourceId, ALSourceb.Looping, true);
		AL.SourcePlay(sourceId);

<br />

The code that worked in OpenTK 3.3.3 is as follows.

		//OpenTK 3.3.3
		AudioContext context = new AudioContext();

		int bufferId = AL.GenBuffer();
		int sourceId = AL.GenSource();
		int state;

		int channels, bits_per_sample, sample_rate;
		byte[] sound_data = LoadWave(
			File.Open(filename, FileMode.Open)
			, out channels
			, out bits_per_sample
			, out sample_rate);
		AL.BufferData(
			bufferId
			, GetSoundFormat(channels, bits_per_sample)
			, sound_data
			, sound_data.Length
			, sample_rate);

		AL.Source(sourceId, ALSourcei.Buffer, bufferId);
		AL.Source(sourceId, ALSourceb.Looping, true);
		AL.SourcePlay(sourceId);

<br />

OpenTK.OpenAL 4.7.7 test project(github)

OpenTK 3.3.3 test project(github)

<br />

This is a code I made using code that other people are using on the Internet.

Looking at the OpenTK 3.3.3 code, it seems to work, but I would like to know where the problem is.

I found the following article through a search.

opentk issues

Referring to the code here, I modified it as follows.
It works the way you want it to.

IntPtr unmanagedPointer = Marshal.AllocHGlobal(sound_data.Length);
Marshal.Copy(sound_data, 0, unmanagedPointer, sound_data.Length);

AL.BufferData(
    bufferId
    , GetSoundFormat(channels, bits_per_sample)
    , unmanagedPointer
    , sound_data.Length
    , sample_rate);

The full code can be found 'here'.