kafrust v0.2.5

Summary

• Adds custom producer partitioner callbacks for immediate, batch, and buffered sends.
• Adds synchronous consumer-group RebalanceListener callbacks with assignment snapshots.
• Qualifies callback behavior in the three-broker cooperative multi-member smoke path.

Breaking changes

• None intended for the published 0.2.x API. The project remains pre-1.0 and public APIs are still alpha.

Migration notes

• Existing users do not need changes.
• New routing integrations can use ProducerConfig::partitioner or partitioner_handler.
• Consumer-group lifecycle integrations can use ConsumerGroupConfig::rebalance_listener.

Compatibility evidence

• Live Kafka Smoke run 31557534371 passed all 13 broker, security, ACL, KIP-848, and multi-broker jobs.
• kafrust-protocol was published before kafrust.
• docs.rs returned HTTP 200 for both published crates.
• Fresh Rust 1.81 projects compiled the published client with default and tls features.

Verification

• MSRV workspace check, tests, Clippy, rustdoc, package dry-runs, and fresh-project checks passed.

Known limits

• Production OAuth/OIDC provider and signed JWT/JWKS qualification remains open.
• Non-Tokio and synchronous client support remains blocked.
• Broader transaction, KIP-848, workload, and long-duration failure qualification remains before a 1.0 replacement claim.