IntKeySet creates a Int from a keys of a map[int](? extends interface{}).

NewInt creates a Int from a list of values.

NewString creates a String from a list of values.

StringKeySet creates a String from a keys of a map[string](? extends interface{}).

Int sets.Int is a set of ints, implemented via map[int]struct{} for minimal memory consumption.

String sets.String is a set of strings, implemented via map[string]struct{} for minimal memory consumption.