Adding some shared state to a TaskGroup without abandoning structured concurrency?

yeah, that’s what i ended up using. i’m now entangled in Ironing out `ManagedBuffer` API wrinkles - #20 by 3405691582 , so i don’t even know if this is the right move anymore.

if it’s not already obvious, all i’m really trying to achieve here is an immutable, concretely-typed [(UInt8, [IP.V6: KnownPeer])] array that also conforms to AtomicReference, since Array itself is a struct. the whitelist type itself has yet to grow additional stored arrays that would justify a third layer of indirection.