Hello, I'm asking for code and design review for `io-region` library. It is already on Hackage for convenience and easy access to haddock: https://hackage.haskell.org/package/io-region Manual exception handling in Haskell almost never is a good idea, except probably trivial cases where `bracket` is enough. A number of special libraries where created to help with exception handling. `io-regions` is one of them. Initially it was an attempt to solve the double-throw issue, but I found it unsolvable in library without changes in language itself. So now it is an attempt to design easy to use API with a bit different set of trade-offs. The library is based on idea of regions that own resources. The resources are released when the region is closed. Early releasing and ownership transferring are supported. Types are *not* used to prevent use-after-free errors. The API is not monadic, and it is the biggest difference from other libraries. Regions are first-class citizens, so you can manipulate them, pass as arguments to functions, send to other thread, store in data types. Such flexibility has its cost -- a bit more manual management. The implementation is based on STM and is thread safe, that allows e.g. atomic ownership transferring between threads. The nearest competitor I think is `resourset` package, and I still recommend it by default. Though I convinced myself that `io-region` is good enough, and I'm using it in productions (for two weeks already :) ) Thanks, Yuras