A unique identifier for message deduplication.

File: AWS.SNS.pas 

Namespace: AWS.SNS 

Module: Appercept AWS SDK for Delphi 

Optional. Only applies to FIFO topics. The MessageDeduplicationId can contain up to 128 alphanumeric characters (a-z, A-Z, 0-9) and punctuation (!"#$%&'()*+,-./:;<=>?@[]^_`{|}~).