Returned when an added key already exists in the set.
Returned when a requested item does not exist in the set.
Returned when a nil item is added. Nil values are considered expired and invalid.
Interface for an item storeable in the set
New creates a new set with case-insensitive keys
Add item to this set if it does not exist already.
Clear removes all items and returns the number removed.
Each loops over every item while holding a read lock and applies fn to each element.
Get returns an item with the given key.
In checks if an item exists in this set.
Len returns the size of the set right now.
ListPrefix returns a list of items with a prefix, normalized. TODO: Add trie for efficient prefix lookup
Remove item from this set.
Replace oldKey with a new item, which might be a new key. Can be used to rename items.
Set item to this set, even if it already exists.