{- |
  Like `cMapM_`, but use at most N threads.
-}
cMapMN_ :: Int -> (a -> IO b) -> [a] -> IO ()
cMapMN_ n f = concurrentN_ n . map f
cMapMN_ :: Int -> (a -> IO b) -> [a] -> IO ()
cMapMN_ n f = concurrentN_ n . map f
cMapMN_ n f = concurrentN_ n . map f