[AGiorgetti]

Summary

Closes #109.

• Align asynchronous observer reads with synchronous enumeration: check disposal before each cursor advance across all seven read routes.
• Keep callbacks and batches already in flight uninterrupted; disposal does not itself cancel a driver operation.
• Add deterministic gated tests and a Breaking Changes / migration note.

Breaking change

An active async read now reports ObjectDisposedException through its existing error path when it next attempts to advance its cursor after engine disposal. Callers needing prompt interruption should cancel and await active reads before disposing the engine.

Verification

• Test-first: 42 failing cases before the fix; focused suite expanded to 98 passing cases.
• All 98 focused tests passed on net472, net8.0, net9.0 and net10.0 with MongoDB Driver 3.0.0 and 3.13.0 (eight lanes).
• Full net10.0 / Driver 3.13.0 suite: 1,236 passed, zero skipped.
• Independent review completed; CRLF-aware whitespace check passed.

Co-authored-by: Alessandro Giorgetti alessandro.giorgetti@live.com
Co-authored-by: Codex (OpenAI) codex@openai.com