Error returned by fallible SQS delivery. Used by Scheduler’s DLQ
routing, which must distinguish “target queue missing” from
“delivered successfully” to decide whether to send to the
DeadLetterConfig.Arn.
Outbound email dispatch used by services that emulate AWS flows that
route through SES (Cognito verification, etc.) without taking a direct
dependency on the SES crate.
Cross-service KMS hook: services that accept a KmsKeyId (Secrets
Manager, SSM SecureString, S3 SSE-KMS, SQS / SNS / DynamoDB
encrypted resources) call this so that real KMS calls happen, the
invocation is recorded for introspection, and the returned blob is
decryptable by the public KMS API.