úÎq5Two ways a computation of type  a can end. :Spawn a concurrent computation. Produces an action which  demands a . :Spawn a concurrent computation. Produces an action which B demands the result. Any exception from the original computation 5 is re-thrown when and where the result is demanded.  spawn-0.1Control.Concurrent.SpawnResultspawnTryspawnghc-prim GHC.TypesIO