Add xmldoc explaining thread safety limitations of `IModelManager` "events"
Add xmldoc explaining thread safety limitations of `IModelManager` "events"

NeoAdonis/osu,ppy/osu,smoogipoo/osu,smoogipoo/osu,smoogipooo/osu,smoogipoo/osu,ppy/osu,NeoAdonis/osu,peppy/osu-new,NeoAdonis/osu,UselessToucan/osu,UselessToucan/osu,peppy/osu,peppy/osu,peppy/osu,ppy/osu,UselessToucan/osu