Github user mikaelstaldal commented on the issue:
https://github.com/apache/logging-log4j2/pull/110
2.9.1 is now released, and the next release will (most likely) be 2.10.0
which will include this. We have no date set for that release, but historically
there has been at least three months between minor releases of Log4j 2.x, and
2.9.0 was released one month ago.---
