Hydra

The update to version 0.9.7 required changes to Promise body signatures, as admitted in the 'Updating to >=0.9.7' section, which can disrupt existing codebases and increase migration effort.

The await function uses semaphores and can cause deadlocks if called in the main thread, as warned in the async/await section, requiring careful thread management to avoid UI freezes.

Implementing cancellable promises requires manual checks for operation status and proper handling, adding complexity and potential for errors, as shown in the detailed cancellable promises example.

With Swift's native concurrency features evolving (e.g., Swift 5.5+), Hydra might become less necessary over time, leading to maintenance overhead for teams adopting it.