code: public static Map<String,String> getExtensions() {
  		 StackInfo result = MDC.get();
  		 if (result == null) {
  			 return StackInfo.collectExtensions();
  		 } else {
  			 return result.extensions;
  		 }
  	 }
docs: Returns context extensions from the current stack. It is called by log handler
  to get extensions which are either passed for the record in a request or
  obtained from the thread directly.
  
  @return extensions from the stack.