dotnet/BenchmarkDotNet

I trying to write a benchmark for a custom stream class, the programs is something like

[GenericTypeArguments(typeof(byte))]
[GenericTypeArguments(typeof(long))]
public class WriteSequences<T> where T : struct
{
    private T[]? _data;
    private MyStream? _stream;

    [GlobalSetup]
    public void GlobalSetup() => _data = ArrayPool<T>.Shared.Rent(8192);

    [IterationSetup]
    public void IterationSetup() => _stream = new MyStream();

    [IterationCleanup]
    public void IterationCleanup() => _stream = null;

    [GlobalCleanup]
    public void GlobalCleanup() => ArrayPool<T>.Shared.Return(_data!);

    [Benchmark(OperationsPerInvoke = 100)]
    [InvocationCount(30000)]
    public void Encoding_Array() => _stream!.WriteSequence(_data!);
}

But I keep getting OutOfMemoryException, here MyStream implementation allocates memory when required using new byte[] but the only reference to this arrays is in MyStream, not clear to me how to get this to work