echo :: WS.Connection -> IO ()
echo conn = forever $ do
    msg <- WS.receiveDataMessage conn
    WS.sendDataMessage conn msg
echo :: WS.Connection -> IO ()
echo conn = forever $ do
    msg <- WS.receiveDataMessage conn
    WS.sendDataMessage conn msg
echo conn = forever $ do
    msg <- WS.receiveDataMessage conn
    WS.sendDataMessage conn msg