v4.3.0

• New: optional Rust kernel backend (use_kernel=True). Adds an alternative connection path backed by the native databricks-sql-kernel client (a Rust core exposed via PyO3), installable with the new databricks-sql-connector[kernel] extra. The kernel talks to Databricks over the SEA (Statement Execution API) HTTP transport — not Thrift — with CloudFetch and inline-Arrow result fetching, so use_kernel=True gives you a modern SEA-native client through the same DB-API surface. Supports PAT, OAuth M2M, and OAuth U2M auth. Requires Python >= 3.10 (the kernel wheel is cp310-abi3); on older interpreters the extra is a no-op and use_kernel=True raises a clear ImportError. The default backend remains Thrift — opt in per connection.
• Kernel backend behavior is aligned with the Thrift backend so application code works the same either way: consistent cursor-state tracking (query_id / get_query_state), metadata (catalogs/schemas/tables/columns with JDBC-style filter semantics and case-insensitive table_types), DML rowcount, server-sourced async execution state, sync cancel(), fail-loud staging/volume operations, and structured error context (SQLSTATE, diagnostic info). Kernel logs surface through Python logging under the databricks.sql.kernel logger (#824, #825, #830, #838, #839 by @vikrantpuppala)
• Revert the thrift 0.23.0 bump that broke installation on DBR LTS (ES-1960554) (#840 by @vikrantpuppala)