feat: ensure we can async-cancel all async types supported

[k13gomez]

• Implement AsyncCancellable on all supported async types
• Ensure we can attempt at best effort to interrupt all supported async types
• Replace WeakHashMap with Caffeine WeakKeys cache

[gemini-code-assist]

Summary of Changes

Hello @k13gomez, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request refines the asynchronous cancellation model within the futurama library. It introduces a more comprehensive and consistent approach to interrupting various async constructs, ensuring that cancellation requests are handled effectively across different types. The changes also include an optimization to the internal state management for cancellation, leading to better resource utilization and performance.

Highlights

• Enhanced Asynchronous Cancellation: The pull request significantly improves the cancellation capabilities for all supported asynchronous types within the futurama library, including Future, IDeref, CompletableFuture, Deferred, and core.async channels. This ensures that asynchronous operations can be interrupted more reliably and consistently.
• Best-Effort Interruption: New mechanisms are in place to attempt best-effort interruption for all supported async types, allowing for more responsive cancellation of long-running or blocked operations.
• Improved Cancellation State Management: The underlying storage for cancellation state has been upgraded from WeakHashMap to Caffeine WeakKeys cache. This change provides a more efficient and memory-friendly way to track the cancellation status of async items, automatically removing entries when they are no longer referenced.
• New Load Tests for Cancellation: New load tests have been added for both async and thread tasks to thoroughly verify the robustness and performance of the enhanced cancellation logic under high concurrency.

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[gemini-code-assist]

Code Review

This pull request introduces a robust and well-designed mechanism for cancelling various async types supported by the library. The key changes include implementing the AsyncCancellable protocol for all supported types, replacing the state management with a high-performance Caffeine cache, and refactoring the core macros to support cancellation. The test coverage has also been significantly improved. The changes are excellent overall. I have one critical comment regarding a dependency version and a medium-severity suggestion to improve consistency.