In my opinion, network programming in Haskell should use strict evaluation except atomicModifiyIORef', to avoid space leak. Strict and StrictData language extension are introduced in GHC 8.0 and it's days of GHC 8.6. So, it's good time to introduce them to network.

For this purpose, all undefined should be removed. It's very easy. But during this work, I experienced that undefined are evaluated even if they are removed from the source code. The reason is here: https://gitlab.haskell.org/ghc/ghc/issues/16810

When such inlinable functions are fixed in GHC 8.8, I would like to add the following to network.cabal:

  if impl(ghc >= 8.8)
      Default-Extensions:  Strict StrictData