warp-tls: Issues with "ability to load TLS credentials from IORefs"

[bitc]

@vdukhovni left some very insightful comments on the pull request Add the ability to load TLS credentials from IORefs:

#806 (review)

The comments were not addressed by the authors of warp-tls, but I believe that that they are valid points that reveal shortcomings in the current implementation. I recommend reading the original comments since it is very well explained. My understanding is that there are 2 issues:

1. A single IORef should be used instead of multiple IORefs (to avoid race condition by allowing atomic update)
2. The API should encourage proper use of certificate chains

Thank you