Streamly.Internal.Control.ForkIO

Stolen from the async package. The perf improvement is modest, 2% on a thread heavy benchmark (parallel composition using noop computations). A version of forkIO that does not include the outer exception handler: saves a bit of time when we will be installing our own exception handler.

Fork a thread that is automatically killed as soon as the reference to the returned threadId is garbage collected.

Fork a thread that is automatically killed as soon as the reference to the returned threadId is garbage collected.