purge :: Handle -> IO ()
purge (Handle _ cookie ioref) = do
  tm <- getSystemTimerManager
  unregisterTimeout tm cookie
  executeOnce ioref
purge :: Handle -> IO ()
purge (Handle _ cookie ioref) = do
  tm <- getSystemTimerManager
  unregisterTimeout tm cookie
  executeOnce ioref
purge (Handle _ cookie ioref) = do
  tm <- getSystemTimerManager
  unregisterTimeout tm cookie
  executeOnce ioref