I noticed that the current MemoryTarget implementation has a few caveats:

• Changes to the MaxLogsCount property doesn't trim the list.
• If MaxLogCount is positive (n), an insertion cost is O(n) (because of a call to RemoveAt(0))
• Enumeration of logs block the writers (!)

It appears that I have a resizable circular buffer implementation that can solve those issues. It's just missing some methods from IList (insert, removeAt) but can serve as a drop in replacement of ThreadSafeList.