SkinProvidingContainer
Currently `protected` functionality for use in custom `SkinProvidingContainer`s, can be exposed to public constructors if it need to later on, but I'm not sure about doing that opposed to just nesting multiple `SkinProvidingContainer`.
OsuUserInputManager
IStorageResourceProvider
user_id
ScoreInfo
LegacySkinTransformer
ISkin
ISkinSource
NextSingle
StatelessRNG