A snapshot resource. Snapshots are used in subscriptions.seek operations, which allow you to manage message acknowledgments in bulk. That is, you can set the acknowledgment state of messages in an existing subscription to the state captured by a snapshot.
The snapshot is guaranteed to exist up until this time. A newly-created snapshot expires no later than 7 days from the time of its creation. Its exact lifetime is determined at creation by the existing backlog in the source subscription. Specifically, the lifetime of the snapshot is 7 days - (age of oldest unacked message in the subscription). For example, consider a subscription whose oldest unacked message is 3 days old. If a snapshot is created from this subscription, the snapshot -- which will always capture this 3-day-old backlog as long as the snapshot exists -- will expire in 4 days. The service will refuse to create a snapshot that would expire in less than 1 hour after creation.
A timestamp in RFC3339 UTC "Zulu" format, with nanosecond resolution and up to nine fractional digits. Examples: "2014-10-02T15:01:23Z" and "2014-10-02T15:01:23.045123456Z".