docup why bracketOnError in accept loop

Author: complyue

Network/Socket.hs

@@ -62,6 +62,10 @@
 -- >             return sock
 -- >     loop sock = forever $ E.bracketOnError (accept sock) (close . fst)
 -- >         $ \(conn, _peer) -> void $
+-- >             -- 'forkFinally' alone is unlikely to fail thus leaking @conn@,
+-- >             -- but 'E.bracketOnError' above will be necessary if some
+-- >             -- non-atomic setups (e.g. spawning a subprocess to handle
+-- >             -- @conn@) before proper cleanup of @conn@ is your case
 -- >             forkFinally (server conn) (const $ gracefulClose conn 5000)
 --
 -- > {-# LANGUAGE OverloadedStrings #-}

examples/EchoServer.hs

@@ -39,4 +39,8 @@ runTCPServer mhost port server = withSocketsDo $ do
             return sock
     loop sock = forever $ E.bracketOnError (accept sock) (close . fst)
         $ \(conn, _peer) -> void $
+            -- 'forkFinally' alone is unlikely to fail thus leaking @conn@,
+            -- but 'E.bracketOnError' above will be necessary if some
+            -- non-atomic setups (e.g. spawning a subprocess to handle
+            -- @conn@) before proper cleanup of @conn@ is your case
             forkFinally (server conn) (const $ gracefulClose conn 5000)