public boolean isTtlUpdated() {
    return expirationTime == Utils.Infinite_Time;
  }
A TTL-UPDATE to cloud sets the expirationTime to -1 in Azure blob metadata.
Additionally, a blob can be uploaded to Azure with expirationTime to -1.
Both these cases are indistinguishable in cloud because it is not a log-structured file on disk.
Both these cases do not warrant a ttl-update, and therefore we must return false when the expiry is -1.
@return True if expirationTime = -1, else false.
ambry-cloud/src/main/java/com/github/ambry/cloud/CloudBlobMetadata.java