Optional hedgeOptional maxMax secondary read staleness in seconds, Minimum value is 90 seconds.最大二次读取过期时间（秒），最小值为90秒。
Optional readOptional maxOptional mode?: ReadPreferenceModeOptional preference?: ReadPreferenceModeOptional tags?: TagSet[]Optional readOptional sessionGenerated using TypeDoc
Server mode in which the same query is dispatched in parallel to multiple replica set members.服务器模式，其中将同一查询并行调度到多个副本集成员。