I do not want to hijack this thread, nor do I intend to ruin its success. I've seen quite a few logging approaches in Swift over the past few years and I also stumbled into few corners where I wished we had more flexibility on how we can obtain logs.
By the end of the day logging is just another way of printing a message to some sort of destination stream. That makes me wonder of we potentially could improve the Streaming API in the stdlib and either generalize print for logging, or build a standalone API on top of the improvements.
Here is one thread which I wish we could pursue as part of this discussion (if that's a reasonable thing to do):