static boolean isEnabledFor(Level level) {
        return (level.levelInt >= INTERNAL_VERBOSITY.levelInt);
    }
This system property controls the internal level of chattiness
of SLF4J. Recognized settings are "INFO", "WARN" and "ERROR". The default value is "INFO".
slf4j-api/src/main/java/org/slf4j/helpers/Reporter.java