Make sure queue group is written to wire (#414)

* Make sure queue group is written to wire

* Test fix

Author: mtmk

src/NATS.Client.Core/Commands/ProtocolWriter.cs

@@ -114,7 +114,7 @@ public void WriteSubscribe(IBufferWriter<byte> writer, int sid, string subject,
 
         if (queueGroup != null)
         {
-            written = _subjectEncoding.GetBytes(subject, span);
+            written = _subjectEncoding.GetBytes(queueGroup, span);
             span[written] = (byte)' ';
             size += written + 1;
             span = span[(written + 1)..];

tests/NATS.Client.Core.Tests/ProtocolTest.cs

@@ -103,6 +103,32 @@ await Retry.Until(
         proxy.Dispose();
     }
 
+    [Fact]
+    public async Task Subscription_queue_group()
+    {
+        await using var server = NatsServer.Start();
+        var (nats, proxy) = server.CreateProxiedClientConnection();
+
+        await using var sub1 = await nats.SubscribeCoreAsync<int>("foo", queueGroup: "group1");
+        await using var sub2 = await nats.SubscribeCoreAsync<int>("foo", queueGroup: "group2");
+
+        await Retry.Until(
+            "frames collected",
+            () => proxy.ClientFrames.Count(f => f.Message.StartsWith("SUB foo")) == 2);
+
+        var frames = proxy.ClientFrames.Select(f => f.Message).ToList();
+
+        foreach (var frame in frames)
+        {
+            _output.WriteLine($"frame: {frame}");
+        }
+
+        Assert.StartsWith("SUB foo group1 ", frames[0]);
+        Assert.StartsWith("SUB foo group2 ", frames[1]);
+
+        await nats.DisposeAsync();
+    }
+
     [Fact]
     public async Task Publish_empty_message_for_notifications()
     {