oh yes, ipython 5+ uses threads in prompt handling. thus an extension can be started in a tab completion thread and then called in the main thread, or the other way around.
in some cases initialisation from a non-main thread might not even be possible, due to lacking functionalty. A good example is ECL on FreeBSD, where GC is like this (well, was, it is now fixed in GC dev, see https://github.com/ivmai/bdwgc/issues/180) -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
