public void FsTrim()
{
int mapEntriesLength = Header.MapEntryCount * MapEntryLength;
long dataEnd = MapEntries.Max(x => x.PhysicalOffsetEnd);
MapEntryStorage.Slice(mapEntriesLength).Fill(SaveDataFileSystem.TrimFillValue);
BaseStorage.Slice(dataEnd).Fill(SaveDataFileSystem.TrimFillValue);
}