private void setLevel(org.apache.log4j.Logger logger, Level level) {
        Level currentLevel = logger.getLevel();
        if (currentLevel == null)
            currentLevel = logger.getEffectiveLevel();

        if (level.equals(currentLevel)) {
            log.debug("Skipping update for logger {} since its level is already {}", logger.getName(), level);
            return;
        }

        log.debug("Setting level of logger {} (excluding children) to {}", logger.getName(), level);
        logger.setLevel(level);
        lastModifiedTimes.put(logger.getName(), time.milliseconds());
    }
Retrieve all known loggers within a given namespace, creating an ancestor logger for that
namespace if one does not already exist
@param namespace the namespace that the loggers should fall under; may not be null
@return all loggers that fall under the given namespace; never null, and will always contain
at least one logger (the ancestor logger for the namespace)
connect/runtime/src/main/java/org/apache/kafka/connect/runtime/Loggers.java