public int getSnapshotVersion() {
    return snapshotVersion;
  }
The snapshot version is generally the number of modifications to the account that were expected to have occurred
before the current time. This is used to validate that there were no unexpected account modifications that could be
inadvertently overwritten by an account update.
@return the expected version for the account record.
ambry-api/src/main/java/com/github/ambry/account/Account.java