A counter per key
A drop-in replacement for
BTreeMap, where the keys have the property of being array indices. Some values may be missing. Much more efficient at operations on individual objects, because it just becomes a simple array lookup.
Convenience functions around a string->string map
Use when your key is just PartialEq, not Ord or Hash.
FixedMap. From a particular key, extract a
usize. These values should be roughly contiguous; the space used by the
O(n)with respect to the largest value returned here.