ConcurrentDictionary AddOrUpdate method
ConcurrentDictionary (unlike Dictionary) has a useful AddOrUpdate method
Exploring the new list pattern
Exploring the new list and slice pattern coming with C# 11
Setting readonly variable using init
Readonly variable can be set using an init only setter
Managing multi-thread access with ReaderWriterLockSlim
Using ReaderWriterLockSlim to allow concurrent reading but exclusive writing