Again on breaking loops at Haskell

I have a small piece of code that receives frames on a zeromq Pull socket and displays it in a opencv window:

module Main where

import           Control.Monad
import qualified OpenCV as CV
import           System.ZMQ4.Monadic
import           System.Exit

main :: IO()
main = runZMQ $ do
  receiver <- socket Pull
  bind receiver "tcp://*:5554"

  -- do some stuff not relevant

  forever $ do
    buffer <- receive receiver
    let img = CV.imdecode CV.ImreadUnchanged buffer -- simple decoder
    liftIO $ CV.withWindow "Video" $ \window -> do
        CV.imshow window img
        key <- CV.waitKey 10
        when (key == 27) exitSuccess -- <- UGLY!

What I would like to find is a way to break the loop that allows me more control. I'm aware of the EitherT solution proposed by Gabriel Gonzalez here (that I like very much) but I'm not able to implement it in the CV.withWindow context, for example:

quit :: (Monad m) => e -> EitherT e m r
quit = left

loop :: (Monad m) => EitherT e m a -> m e
loop = fmap (either id id) . runEitherT . forever

main :: IO()
main = runZMQ $ do
  receiver <- socket Pull
  bind receiver "tcp://*:5554"

  loop $ do
    buffer <- receive receiver
    let img = CV.imdecode CV.ImreadUnchanged buffer -- simple decoder
    liftIO $ CV.withWindow "Video" $ \window -> do
        CV.imshow window img
        key <- CV.waitKey 10
        when (key == 27) $ quit ()

But of course quit wraps the argument in a Left and this solution doesn't compile.

Read and write an IORef, and use whileM_.

main = runZMQ $ do
    receiver <- socket Pull
    bind receiver "tcp://*:5554"
    continue <- liftIO $ newIORef True

    whileM_ (liftIO $ readIORef continue) $ do
        buffer <- receive receiver
        let img = CV.imdecode CV.ImreadUnchanged buffer -- simple decoder
        liftIO . CV.withWindow "Video" $ \window -> do
            CV.imshow window img
            key <- CV.waitKey 10
            when (key == 27) $ writeIORef continue False

Or have your loop call itself explicitly as appropriate:

main = runZMQ $ do
    receiver <- socket Pull
    bind receiver "tcp://*:5554"

    let loop = do
            buffer <- receive receiver
            let img = CV.imdecode CV.ImreadUnchanged buffer -- simple decoder
            key <- liftIO . CV.withWindow "Video" $ \window -> do
                CV.imshow window img
                CV.waitKey 10
            when (key /= 27) loop

    loop