During May 2025, Ben Barzen enhanced the aws/s2n-quic repository by implementing handshake cancellation and explicit error handling for application data generation. He updated the make_application_data callback to return a Result, allowing the handshake process to terminate early and propagate clear error messages when data generation failed. Leveraging Rust and applying principles from cryptography and network programming, Ben utilized the path_secrets_ready callback to cancel handshakes when preconditions were unmet, reducing unnecessary cryptographic operations. This work improved handshake reliability, clarified user-facing errors, and reduced support overhead, demonstrating a thoughtful approach to callback-driven API design and robust error signaling within the handshake lifecycle.