This PR implements performance optimizations across the MinIO Rust SDK, focusing on reducing latency and improving throughput for high-performance use cases like DataFusion/ObjectStore integration. Key improvements include signing key caching, HTTP/2 optimization, region lookup bypass, and fast-path APIs.
Key Changes:
Performance optimizations: Signing key caching (4 HMAC ops saved per request), HTTP/2 adaptive window, optimized query/header string building, and a fast-path GET API
Bug fixes: Corrected multipart copy logic, changed stat_object to use HEAD method, fixed region handling in tests
API enhancements: Added get_object_fast(), into_boxed_stream(), and into_bytes() methods for high-performance scenarios
