Client Disconnection客户端断开
Starting in MongoDB 4.2, if the client that issued the getnonce disconnects before the operation completes, MongoDB marks the getnonce for termination (i.e. killOp on the operation).从MongoDB 4.2开始，如果发出getnonce的客户端在操作完成之前断开连接，MongoDB会将getnonce标记为终止（即操作上killOp）。