NativeMemoryArray_Blog2.cs

public static async Task ReadFromAsync(NativeMemoryArray<byte> buffer, Stream stream, CancellationToken cancellationToken = default)
{
    var writer = buffer.CreateBufferWriter();

    int read;
    while ((read = await stream.ReadAsync(writer.GetMemory(), cancellationToken).ConfigureAwait(false)) != 0)
    {
        writer.Advance(read);
    }
}

public static async Task WriteToAsync(NativeMemoryArray<byte> buffer, Stream stream, CancellationToken cancellationToken = default)
{
    foreach (var item in buffer.AsMemorySequence())
    {
        await stream.WriteAsync(item, cancellationToken);
    }
}