Upon successful completion of the operation, this function is called to record that the operation was successful.
After a failed operation call, this function is invoked to refresh the retryToken returned by acquireInitialRetryToken(). This function can either choose to allow another retry and send a new or updated token, or reject the retry attempt and report the error either in an exception or returning an error.
Called before any retries (for the first call to the operation). It either returns a retry token or an error upon the failure to acquire a token prior.
tokenScope is arbitrary and out of scope for this component. However, adding it here offers us a lot of future flexibility for outage detection. For example, it could be "us-east-1" on a shared retry strategy, or "us-west-2-c:dynamodb".