Reactivate Options. with IfUnmodified Since(DateTime ifUnmodifiedSince) 方法
Set a timestamp indicating the last modified time of the resource known to the client. The operation will be performed only if the resource on the service has not been modified since the specified time.
public TaskReactivateOptions withIfUnmodifiedSince(DateTime ifUnmodifiedSince)
the ifUnmodifiedSince value to set
the TaskReactivateOptions object itself.