An alternative approach to achieve idempotency is to define the semantics of a message such that resending the message does not impact the system. For example, rather than defining a message as “Add $10 to account 12345,” we could change the message to “Set the balance of account 12345 to $110.” Both messages achieve the same result if the current account balance is $100. The second message is idempotent because receiving it twice will not have any effect.
