revert changes to greeter server example

dialoptions.go

@@ -415,7 +415,8 @@ func WithTimeout(d time.Duration) DialOption {
 // should try to reconnect to the network address.
 //
 // Note: Go overrides the OS defaults for TCP keepalive time and interval to 15s.
-// To retain OS defaults, use a net.Dialer with the KeepAlive field set to a negative value.
+// To retain OS defaults, use a net.Dialer with the KeepAlive field set to a
+// negative value.
 func WithContextDialer(f func(context.Context, string) (net.Conn, error)) DialOption {
 	return newFuncDialOption(func(o *dialOptions) {
 		o.copts.Dialer = f

examples/helloworld/greeter_server/main.go

@@ -25,7 +25,6 @@ import (
 	"fmt"
 	"log"
 	"net"
-	"time"
 
 	"google.golang.org/grpc"
 	pb "google.golang.org/grpc/examples/helloworld/helloworld"
@@ -48,9 +47,7 @@ func (s *server) SayHello(ctx context.Context, in *pb.HelloRequest) (*pb.HelloRe
 
 func main() {
 	flag.Parse()
-	// Setting KeepAlive to -1 allows the listener to retain OS default TCP keepalive time and interval.
-	lc := net.ListenConfig{KeepAlive: time.Duration(-1)}
-	lis, err := lc.Listen(context.Background(), "tcp", fmt.Sprintf(":%d", *port))
+	lis, err := net.Listen("tcp", fmt.Sprintf(":%d", *port))
 	if err != nil {
 		log.Fatalf("failed to listen: %v", err)
 	}