What does it mean when Snapshot in Firebase Cloud Functions lacks a readTime?

edit

When a Snapshot in Firebase Cloud Functions lacks a readTime, it means that the snapshot is not currently synchronized with the server. This can happen when the snapshot is obtained using the local cache instead of requesting the data from the server. It is important to note that snapshots obtained from the local cache may not be up-to-date with the server data, so it is recommended to use server requests whenever possible to ensure that the data is current. Additionally, when a snapshot lacks a readTime, it cannot be used for server-side triggers or other time-sensitive operations.