Improve resource record implementation in the mdns package.

pkg/mdns/lib/mdns.dart

Index: pkg/mdns/lib/mdns.dart
diff --git a/pkg/mdns/lib/mdns.dart b/pkg/mdns/lib/mdns.dart
index 55682a7b4ca2c2360d0554cb504ef3c130f4e71f..81528137a8c00b5ad6621e12062e48d5f768bb5a 100644
--- a/pkg/mdns/lib/mdns.dart
+++ b/pkg/mdns/lib/mdns.dart
@@ -11,6 +11,9 @@ import 'dart:typed_data';
 
 import 'package:mdns/src/native_extension_client.dart';
 import 'package:mdns/src/native_protocol_client.dart';
+import 'package:mdns/src/constants.dart';
+
+export 'package:mdns/src/constants.dart' show RRType;
 
 /// Client for DNS lookup using the mDNS protocol.
 ///
@@ -51,15 +54,17 @@ abstract class MDnsClient {
   ///
   /// If no answer has been received within the specified [timeout]
   /// this method will complete with the value `null`.
-  Future<InternetAddress> lookup(
-      String hostname, {Duration timeout: const Duration(seconds: 5)});
+  Stream<ResourceRecord> lookup(
+      int type,
+      String name,
+      {Duration timeout: const Duration(seconds: 5)});
 }
 
 // Simple standalone test.
 Future main(List<String> args) async {
   var client = new MDnsClient();
   await client.start();
-  var address = await client.lookup(args[0]);
-  client.stop();
+  ResourceRecord resource = await client.lookup(RRType.A, args[0]).first;
   print(address);
+  client.stop();
 }