A new API: gracefulClose. #417
Also see Kazu's blog post on the design choices in this function 
https://kazu-yamamoto.hatenablog.jp/entry/2019/09/20/165939
touchSocket, unsafeFdSocket: Allow direct access to a socket's file descriptor while providing tools to prevent it from being garbage collected. This also deprecated fdSocket in favor of unsafeFdSocket and withFdSocket. #423
socketToFd: Duplicates a socket as a file descriptor and closes the source socket. #424
As always thank you to network's contributors.