类似于this previous question，你不能单独使用simpleHttp。您需要同时使用Manager和httpLbs才能设置超时。
请注意，您不需要在管理器中设置超时，但您可以为每个请求单独设置它。
下面是一个完整的示例，其行为与上面的函数类似，但允许您修改超时：

import Network.HTTP.Conduit
import Control.Monad (liftM)
import qualified Data.ByteString.Lazy.Char8 as LB

-- | A simpleHttp alternative that allows to specify the timeout
-- | Note that the timeout parameter is in microseconds!
downloadHttpTimeout :: Manager -> String -> Int -> IO LB.ByteString
downloadHttpTimeout manager url timeout = do req <- parseUrl url
                                             let req' = req {responseTimeout = Just timeout}
                                             liftM responseBody $ httpLbs req' manager

main = do manager <- newManager conduitManagerSettings
          let timeout = 15000000 -- Microseconds --> 15 secs
          content <- downloadHttpTimeout manager "http://stackoverflow.com" timeout
          print $ content

我发现以下是Uli的downloadHttpTimeout的一个版本，它更类似于simpleHTTP：

simpleHTTPWithTimeout :: Int -> Request a -> IO (Response LB.ByteString)
simpleHTTPWithTimeout timeout req =
  do mgr <- newManager tlsManagerSettings
     let req = req { responseTimeout = Just timeout }
     httpLbs req mgr

与simpleHTTP的唯一区别是返回类型略有不同，因此可以提取例如响应体，一个使用导管的responseBody而不是Network.HTTP.getResponseBody。

目前，Int不能隐式转换为ResponseTimeout，需要responseTimeoutMicro来转换Int。

import Network.HTTP.Conduit (parseRequest, responseTimeoutMicro)
import Network.HTTP.Simple (
    getResponseBody,
    httpBS,
    setRequestResponseTimeout,
 )
import Prelude

main :: IO ()
main = do
    req <- parseRequest "https://stackoverflow.com"
    let timeout = responseTimeoutMicro 60000000
    let req' = setRequestResponseTimeout timeout req
    resp <- httpBS req
    let content = getResponseBody resp
    print content