code: private static final String[] inferCaller() {
      StackTraceElement[] stack = (new Throwable()).getStackTrace();
      int ix = 0;
      while(ix < stack.length) {
        StackTraceElement frame = stack[ix];
  
        if(!frame.getClassName().equals(LoggingUtil.class.getCanonicalName())) {
          return new String[] { frame.getClassName(), frame.getMethodName() };
        }
        ix++;
      }
  
      return null;
    }
docs: Infer which class has called the logging helper.
  
  While this looks like duplicated code from ELKILogRecord, it is needed here
  to find an appropriate Logger (and check the logging level) for the calling
  class, not just to log the right class and method name.
  
  @return calling class name and calling method name