InvalidationBatch (string)

A unique name that ensures the request can't be replayed. If the CallerReference is new (no matter the content of the Path object), a new distribution is created. If the CallerReference is a value you already sent in a previous request to create an invalidation batch, and the content of each Path element is identical to the original request, the response includes the same information returned to the original request. If the CallerReference is a value you already sent in a previous request to create a distribution but the content of any Path is different from the original request, CloudFront returns an InvalidationBatchAlreadyExists error.