Haskell implementation of Java LinkedHashMap. Underlying HashMap is based on Data.HashMap.Strict. Two different implementations are based on Data.Sequence and Data.IntMap.Strict to keep keys in the order of insertion. Criterion report: https://cdn.rawgit.com/abasko/linkedhashmap/68de7332e80db673e024906321ad2e14c2baa4d1/benchmarks/report.html