haskell@gentoo.org Gentoo Haskell Use the bundled zlib C sources. Requires pkg-config to be False. For windows, this is the default. The (de)compression calls can sometimes take a long time, which prevents other Haskell threads running. Enabling this flag avoids this unfairness, but with greater overall cost. This package provides a pure interface for compressing and decompressing streams of data represented as lazy 'ByteString's. It uses the <https://en.wikipedia.org/wiki/Zlib zlib C library> so it has high performance. It supports the \"zlib\", \"gzip\" and \"raw\" compression formats. It provides a convenient high level API suitable for most tasks and for the few cases where more control is needed it provides access to the full zlib feature set.