.Net: How to extend the ChatHistory class?

[sphenry]

Discussed in #9931

^{Originally posted by MalayAgr December 10, 2024}
I have a scenario where I want to make the ChatHistory class an observable so that other classes can subscribe to changes in the ChatHistory. The extended class would notify the subscribers whenever a message is added to the ChatHistory.

Unfortunately, I just realised that none of the methods used to add messages to the ChatHistory are virtual and hence, cannot be overridden. I was hoping to leverage polymorphism so that the rest of my code doesn't need to change and I can use this observable ChatHistory and the usual ChatHistory class interchangeably.

How can I achieve this?