Add overload for empty requests

src/NATS.Client.Core/INatsConnection.cs

@@ -131,7 +131,7 @@ public interface INatsConnection : IAsyncDisposable
     /// <remarks>
     /// Response can be (null) or one <see cref="NatsMsg{T}"/>.
     /// Reply option's max messages will be set to 1.
-    /// if reply option's timeout is not defined then it will be set to NatsOpts.RequestTimeout.
+    /// If reply option's timeout is not defined, then it will be set to NatsOpts.RequestTimeout.
     /// </remarks>
     ValueTask<NatsMsg<TReply>> RequestAsync<TRequest, TReply>(
         string subject,
@@ -143,6 +143,27 @@ ValueTask<NatsMsg<TReply>> RequestAsync<TRequest, TReply>(
         NatsSubOpts? replyOpts = default,
         CancellationToken cancellationToken = default);
 
+    /// <summary>
+    /// Send an empty request message and await the reply message asynchronously.
+    /// </summary>
+    /// <param name="subject">Subject of the responder</param>
+    /// <param name="replySerializer">Serializer to use for the reply message type.</param>
+    /// <param name="replyOpts">Reply handler subscription options</param>
+    /// <param name="cancellationToken">Cancel this request</param>
+    /// <typeparam name="TReply">Reply type</typeparam>
+    /// <returns>Returns the <see cref="NatsMsg{T}"/> received from the responder as reply.</returns>
+    /// <exception cref="OperationCanceledException">Raised when cancellation token is used</exception>
+    /// <remarks>
+    /// Response can be (null) or one <see cref="NatsMsg{T}"/>.
+    /// Reply option's max messages will be set to 1.
+    /// If reply option's timeout is not defined, then it will be set to NatsOpts.RequestTimeout.
+    /// </remarks>
+    ValueTask<NatsMsg<TReply>> RequestAsync<TReply>(
+        string subject,
+        INatsDeserialize<TReply>? replySerializer = default,
+        NatsSubOpts? replyOpts = default,
+        CancellationToken cancellationToken = default);
+
     /// <summary>
     /// Request and receive zero or more replies from a responder.
     /// </summary>

src/NATS.Client.Core/NatsConnection.RequestReply.cs

@@ -74,6 +74,22 @@ public async ValueTask<NatsMsg<TReply>> RequestAsync<TRequest, TReply>(
         throw new NatsNoReplyException();
     }
 
+    /// <inheritdoc />
+    public ValueTask<NatsMsg<TReply>> RequestAsync<TReply>(
+        string subject,
+        INatsDeserialize<TReply>? replySerializer = default,
+        NatsSubOpts? replyOpts = default,
+        CancellationToken cancellationToken = default) =>
+        RequestAsync<object, TReply>(
+            subject: subject,
+            data: default,
+            headers: default,
+            requestSerializer: default,
+            replySerializer: replySerializer,
+            requestOpts: default,
+            replyOpts: replyOpts,
+            cancellationToken: cancellationToken);
+
     /// <inheritdoc />
     public async IAsyncEnumerable<NatsMsg<TReply>> RequestManyAsync<TRequest, TReply>(
         string subject,

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

@@ -392,4 +392,30 @@ public async Task Request_reply_many_multiple_with_timeout_test()
         await sub.DisposeAsync();
         await reg;
     }
+
+    [Fact]
+    public async Task Simple_empty_request_reply_test()
+    {
+        await using var server = NatsServer.Start();
+        await using var nats = server.CreateClientConnection();
+
+        const string subject = "foo";
+        var cts = new CancellationTokenSource(TimeSpan.FromSeconds(30));
+        var cancellationToken = cts.Token;
+
+        var sub = await nats.SubscribeCoreAsync<int>(subject, cancellationToken: cancellationToken);
+        var reg = sub.Register(async msg =>
+        {
+            await msg.ReplyAsync(42, cancellationToken: cancellationToken);
+        });
+
+        var reply1 = await nats.RequestAsync<object, int>(subject, null, cancellationToken: cancellationToken);
+        var reply2 = await nats.RequestAsync<int>(subject, cancellationToken: cancellationToken);
+
+        Assert.Equal(42, reply1.Data);
+        Assert.Equal(42, reply2.Data);
+
+        await sub.DisposeAsync();
+        await reg;
+    }
 }

tests/NATS.Client.JetStream.Tests/NatsJsContextFactoryTest.cs

@@ -123,6 +123,8 @@ public ValueTask<NatsMsg<TReply>> RequestAsync<TRequest, TReply>(
             CancellationToken cancellationToken = default)
             => throw new NotImplementedException();
 
+        public ValueTask<NatsMsg<TReply>> RequestAsync<TReply>(string subject, INatsDeserialize<TReply>? replySerializer = default, NatsSubOpts? replyOpts = default, CancellationToken cancellationToken = default) => throw new NotImplementedException();
+
         public IAsyncEnumerable<NatsMsg<TReply>> RequestManyAsync<TRequest, TReply>(
             string subject,
             TRequest? data,