Indicates whether this write result was acknowledged. If not, then all other members of this result will be undefined指示是否已确认此写入结果。如果不是，则此结果的所有其他成员都将未定义
The identifier that was inserted. If the server generated the identifier, this value will be null as the driver does not have access to that data插入的标识符。如果服务器生成了标识符，则该值将为null，因为驱动程序无法访问该数据
Indicates whether this write result was acknowledged. If not, then all other members of this result will be undefined指示是否已确认此写入结果。如果不是，则此结果的所有其他成员都将未定义