if(ts>this.deletionTs){return false;}
return true;},getSnapshotAt(ts){if(ts<this.creationTs){if(this.creationTsWasExplicit){throw new Error('ts must be within lifetime of this instance');}
return this.snapshots[0];}
if(ts>this.deletionTs){throw new Error('ts must be within lifetime of this instance');}