Sends a request to the AWS Storage Gateway server running at the
            specified address, and returns the activation key for that server.
            
 Declaration Syntax
 Declaration Syntax Parameters
 Parameters- gatewayAddress (String)
- The DNS name or IP address of a running AWS Storage Gateway
- maxRetries (Int32)
- The maximum number of retries to attempt on failure
- maxBackoff (Int32)
- The maximum backoff time, in milliseconds, for retry attempts. Backoff times between retries rise exponentially until they hit this ceiling.
 Return Value
 Return ValueThe activation key required for some API calls to AWS Storage Gateway.