Control.Concurrent.Async.Warden

A Warden is an owner of Asyncs which cancels them on shutdown.

Nothing in the MVar means the Warden has been shut down.

Run the action with a new Warden, and call shutdown when the action exits.

Create a new Warden.

Shutdown a Warden, calling cancel on all owned threads. Subsequent calls to spawn and shutdown will be no-ops.

Note that any exceptions thrown by the threads will be ignored. If you want exceptions to be propagated, either call wait explicitly on the Async, or use link.

Spawn a new thread owned by the Warden.

Spawn a new thread owned by the Warden.

Spawn a thread with masked exceptions and pass an unmask function to the action.