docs: private T nextUncheck() {
  		if (0 != this.index || false == this.includeStart) {
  			// 非第一个元素或不包含第一个元素增加步进
  			this.current = this.next;
  			if (null != this.current) {
  				this.next = safeStep(this.next);
  			}
  		}
  		index++;
  		return this.current;
  	}