public static void setStage(String parent, String child) {
    if (parent == null) {
      setStage(child);
    } else {
      setStage(parent + ":" + child.replaceFirst("^" + Pattern.quote(parent) + "_?", ""));
    }
  }
Prepends {@code [parent:child]} to all subsequent logs from this thread.
planetiler-core/src/main/java/com/onthegomap/planetiler/util/LogUtil.java