public void CreateAndCleanup()
{
var file = Path.Combine(_tempFolders.CreateRandomTempFolder(), "CreateAndCleanup.mmf");
using (var mmf = new MemoryFile(file, 100))
{
Assert.Equal(100, mmf.FileLength);
var spanAll = mmf.GetSpan();
var span40Len10 = mmf.GetSpan(40, 10);
var bytes = new byte[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
bytes.CopyTo(span40Len10);
Assert.Equal(7, spanAll[47]);
spanAll[^ 1] = 42;