serve: remove deadcode

Signed-off-by: Koichi Shiraishi <zchee.io@gmail.com>

serve.go

@@ -5,9 +5,7 @@ package jsonrpc2
 
 import (
 "context"
-"errors"
 "fmt"
-"io"
 "net"
 "os"
 "time"
@@ -129,23 +127,3 @@ func Serve(ctx context.Context, ln net.Listener, server StreamServer, idleTimeou
 }
 }
 }
-
-// isClosingError reports whether the error occurs normally during the process of
-// closing a network connection.
-//
-// It uses imperfect heuristics that err on the side of false negatives,
-// and should not be used for anything critical.
-func isClosingError(err error) bool {
-if errors.Is(err, io.EOF) {
-return true
-}
-
-// Per https://github.com/golang/go/issues/4373, this error string should not
-// change. This is not ideal, but since the worst that could happen here is
-// some superfluous logging, it is acceptable.
-if err.Error() == "use of closed network connection" {
-return true
-}
-
-return false
-}