code: public static RuntimeException unchecked(final Throwable t) {
  		if (t instanceof RuntimeException) {
  			return (RuntimeException) t;
  		} else {
  			return new RuntimeException(t);
  		}
  	}
docs: 将 Exception 转换为 RuntimeException。
  
  @param t
  原始异常
  @return 运行时异常