Signal interface description.

newSignal :: IO (Signal a)

create a new Signal handle which can be used to broadcast one-off signal values. The Signal is not buffered, but a one-shot synchronisation point.

waitSignal :: Signal a -> IO a

block waiting for next value to be signalled via a Signal handle.

fireSignal :: Signal a -> a -> IO ()

Broadcast a Signal value. All processes blocked via waitSignal will see the value.