SDK 0.4.30

Retry transient connection-establishment failures in sandbox requests within the original deadline, with at most five attempts and bounded backoff. Streaming bodies rewind before retry. Certificate failures, cancellation and ambiguous post-dispatch failures are not replayed. Final errors include the attempt count and underlying exception type.

Sync clients retry identified DNS, refused-connection and unreachable-host errors; async clients retry connector-establishment failures. No backend version change is required for this client behavior.