Since PIDs are not comparable they can not be used with the Set in elm/core.
When using an event/observer pattern in the actor model it is useful to gather PIDs that are observing an event in a Set.
Store PIDs in a Set
Webbhuset.Internal.PID.PID
A PID is an identifier for a Process.
A process is an instance of an Actor / Component
empty : Set
Create an empty set
insert : PID -> Set -> Set
Insert PID in a Set
isEmpty : Set -> Basics.Bool
Check if a Set is empty.
remove : PID -> Set -> Set
Remove a PID from a Set
toList : Set -> List PID
Get all pids as a List