# Functions
MaxKeys functional option defines how many keys to keep.
NewLoadingCache returns a new expirable LRC cache, activates purge with purgeEvery (0 to never purge).
OnEvicted called automatically for expired and manually deleted entries.
PurgeEvery functional option defines purge interval by default it is 0, i.e.
TTL functional option defines TTL for all cache entries.
# Structs
LoadingCache provides expirable loading cache with LRC eviction.
# Type aliases
Option func type.