Elliot.

@nkramer44 any thoughts on this? Should we close this issue?

(notes: will squash this to 1 commit)

(notes: not ready to merge; need @thejohnfreeman to make the Conan changes before we can do this)

@ximinez given conan, what is the best path forward (or not) for this PR?

- goals and matrix here may be useful - there have been so many changes that it may be better to start over and just take what's useful from here...

@ckeshava would you like to pick this up?

(Holding this for 1.12 unless someone requests otherwise)

This has CI failures which need to be resolved (or explained). @ckeshava or @thejohnfreeman - could you have a look?

@HowardHinnant because there have been changes pushed after your earlier approval, could you do a quick re-review?

@nbougalis what are your latest thoughts on this issue? (Given we don't know how to reproduce it, we are inclined to close the issue until we get more information.)