Github user mdvorak commented on the issue:
https://github.com/apache/logging-log4j2/pull/110
@mikaelstaldal I've looked at `GelfLayout`, and it resolves `${}`
expressions during serialization. Is this really nescessary? Looks like pretty
big overhead to me. I've tested only XML config, but expressions are resolved
automatically when parsed. Won't there be a possible conflict? I don't see so
far.---
