in log4j2-ecs-layout/src/main/java/co/elastic/logging/log4j2/EcsLayout.java [200:205]
private static void formatPattern(LogEvent event, PatternFormatter[] formatters, StringBuilder buffer) {
final int len = formatters.length;
for (int i = 0; i < len; i++) {
formatters[i].format(event, buffer);
}
}