@CheckReturnValue
    default public LoggingEventBuilder atDebug() {
        if (isDebugEnabled()) {
            return makeLoggingEventBuilder(DEBUG);
        } else {
            return NOPLoggingEventBuilder.singleton();
        }
    }
Entry point for fluent-logging for {@link org.slf4j.event.Level#DEBUG} level. 
 
@return LoggingEventBuilder instance as appropriate for level DEBUG
@since 2.0
slf4j-api/src/main/java/org/slf4j/Logger.java