Add NoContent instance for NFData

servant/servant.cabal

@@ -109,6 +109,7 @@ library
     , attoparsec             >= 0.13.2.2 && < 0.14
     , bifunctors             >= 5.5.3    && < 5.6
     , case-insensitive       >= 1.2.0.11 && < 1.3
+    , deepseq                >= 1.4.2.0  && < 1.5
     , http-media             >= 0.7.1.3  && < 0.8
     , http-types             >= 0.12.2   && < 0.13
     , mmorph                 >= 1.1.2    && < 1.2

servant/src/Servant/API/ContentTypes.hs

@@ -71,6 +71,8 @@ module Servant.API.ContentTypes
 import           Control.Arrow
                  (left)
 import           Control.Monad.Compat
+import           Control.DeepSeq
+                 (NFData)
 import           Data.Aeson
                  (FromJSON (..), ToJSON (..), encode)
 import           Data.Aeson.Parser
@@ -361,6 +363,8 @@ instance MimeRender OctetStream BS.ByteString where
 data NoContent = NoContent
   deriving (Show, Eq, Read, Generic)
 
+instance NFData NoContent
+
 
 --------------------------------------------------------------------------
 -- * MimeUnrender Instances