úÎ A ÞNoneThe 8 type class, for monads which support a fork operation. The instance for  is simply !, while several very overlapping F instances are provided for composite monads, using the monad-control  package. "An example of a monad which has a  instance that is not simply  a lifted form of  is the  ResourceT monad from the conduit & package, which defines the operation resourceForkIO. The instances H defined here, using the OverlappingInstances extension, will correctly 1 handle the case of monads transformed on top of  ResourceT (assuming a  definition exists for  ResourceT).     monad-fork-0.1Control.Monad.Fork.Class MonadForkforkghc-prim GHC.TypesIObase GHC.Conc.SyncforkIO $fMonadForkt $fMonadForkm $fMonadForkIO