Implementation carried over from v1.

code/MessengerApi.QueryClient.Example/MessengerApi.QueryClient.Example.csproj

@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net9.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\MessengerApi.QueryClient\MessengerApi.QueryClient.csproj" />
+  </ItemGroup>
+
+</Project>

code/MessengerApi.QueryClient.Example/Program.cs

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+using MessengerApi.Model;
+using MessengerApi.Model.Messages;
+using portaloggy;
+
+namespace MessengerApi.Example
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            var logger = new ConsoleLogger() { IsMessageSeverityColoringEnabled = true};
+            var httpClient = new HttpClient();
+
+            // Client 1 will demonstrate querying approach.
+            var client1 = new QueryClient(
+                new Credentials(
+                    "aab8f7e9-ad13-4bf8-bb2e-0cd93d81adc0",
+                    "http://localhost:5259"),
+                httpClient,
+                logger);
+
+            // Client 2 is subscription client waiting for the queries.
+            var client2 = new SubscriptionClient(
+                new Credentials(
+                    "8f73f683-7cb3-40df-998e-6e604aef0e53",
+                    "http://localhost:5259"),
+                httpClient,
+                logger);
+
+            var user1 = Guid.Parse("f696442b-e8dc-4074-b34f-94bcece8e74b");
+            var user2 = Guid.Parse("15d97720-f5b7-47aa-9c1a-71f98b0b9248");
+
+            // Subscribe client 2 to questions.
+            var client2Subscription = client2.Subscribe("TEST");
+
+            client2Subscription.OnMessage += (s, m) =>
+            {
+                logger.Info($"Received subscribed message - {m.Payload}");
+                client2.SendMessage(new OutboxMessage
+                {
+                    ToUserId = m.Sender,
+                    Payload = "ANSWER",
+                    PayloadType = m.PayloadType
+                });
+            };
+
+            // Demonstrate query pipeline. Client 1 sends query and waits for response.
+            // Client 2 is subscribed to those messages and will send an answer right away.
+            var answer = client1.Query(new OutboxMessage
+            {
+                ToUserId = user2,
+                PayloadType = "TEST",
+                Payload = "QUESTION"
+            }).GetAwaiter().GetResult();
+
+            logger.Info($"Received answer message to my query with payload: {answer.Payload}.");
+        }
+    }
+}