Prevent DiscordClient from being inherited

Created by: uwx

Summary

Fixes an InvalidOperationException in the EventWaiter<T> constructor by disallowing something which should have never been allowed to begin with.

Details

This is the exception: It is caused by enumerating DeclaredFields looking for an event field. When you inherit DiscordClient, all the event fields will be in the superclass, so DeclaredFields will not return anything useful. The only way around it would be really annoying, especially when you could just mark DiscordClient as sealed and call it a day.

Changes proposed

• Add sealed modifier to DiscordClient

Notes

Untested