Add Reliable Producer Documentation (#112)

* Add Reliable Producer Documentation and Example
Signed-off-by: Gabriele Santomaggio <G.santomaggio@gmail.com>

Author: Gsantomaggio

Examples/Reliable/README.md

@@ -0,0 +1,4 @@
+Reliable Examples
+---
+
+How to use the reliable producer and consumer

Examples/Reliable/ReliableProducer.cs

@@ -0,0 +1,58 @@
+using System.Buffers;
+using System.Text;
+using RabbitMQ.Stream.Client;
+using RabbitMQ.Stream.Client.Reliable;
+
+namespace example;
+
+public class ReliableProducer
+{
+    public async Task StartDefaultConfigurations()
+    {
+        var config = new StreamSystemConfig();
+        const string stream = "my-reliable-stream";
+        var system = await StreamSystem.Create(config);
+        await system.CreateStream(new StreamSpec(stream)
+        {
+            MaxLengthBytes = 2073741824
+        });
+        const int totalMessages = 1_000;
+       
+        var reliableProducer = await ReliableProducer.CreateReliableProducer(new ReliableProducerConfig()
+        {
+            StreamSystem = system,
+            Stream = stream,
+            Reference = "my-reliable-producer",
+            ConfirmationHandler = confirmation =>
+            {
+                Console.WriteLine(confirmation.Status == ConfirmationStatus.Confirmed
+                    ? $"Confirmed: Publishing id {confirmation.PublishingId}"
+                    : $"Not Confirmed: Publishing id {confirmation.PublishingId}, error: {confirmation.Status} ");
+                return Task.CompletedTask;
+            }
+        });
+        var start = DateTime.Now;
+        for (var i = 0; i < totalMessages; i++)
+        {
+            // standard send
+            await reliableProducer.Send(new Message(Encoding.UTF8.GetBytes($"hello {i}")));
+        }
+
+        // sub-batch
+        var listMessages = new List<Message>();
+        for (var i = 0; i < 100; i++)
+        {
+            listMessages.Add(new Message(Encoding.UTF8.GetBytes($"hello {i}")));
+        }
+
+        // in this case you will receive back one confirmation with all the messages
+        await reliableProducer.Send(listMessages, CompressionType.Gzip);
+
+
+        Console.WriteLine($"End...Done {DateTime.Now - start}");
+        // just to receive all the notification back
+        Thread.Sleep(2000);
+        await reliableProducer.Close();
+        
+    }
+}

README.md

@@ -29,6 +29,8 @@
       - [Track Offset](#track-offset)
     - [Handle Close](#handle-close)
     - [Handle Metadata Update](#handle-metadata-update)
+    - [Reliable](#reliable)
+      - [Reliable Producer](#reliable-producer)
     - [Build from source](#build-from-source)
     - [Project Status](#project-status)
 
@@ -220,7 +222,6 @@ var producer = await system.CreateProducer(
         Stream = "my_stream",
     });
 ```
-
 Consider a Producer instance like a long-lived object, do not create one to send just one message.
 
 | Parameter               | Description                            | Default                        |
@@ -408,6 +409,81 @@ You can use `MetadataHandler` to handle it:
    },
  }
 ```
+### Reliable 
+ - Reliable Producer
+ - Reliable Consumer (not ready yet)
+
+### Reliable Producer
+Reliable Producer is a smart layer built up of the standard `Producer`. </b>   
+The idea is to leave the user decides what to use, the standard or reliable producer. </b>
+
+The main features are:
+- Provide publishingID automatically
+- Auto-Reconnect in case of disconnection
+- Trace sent and received messages
+- Invalidate messages
+- Handle the metadata Update
+
+#### Provide publishingID automatically
+Reliable Producer retrieves the last publishingID given the producer name. </b>
+Zero(0) is the default value in case there is no a publishingID.
+
+#### Auto-Reconnect
+Reliable Producer restores the TCP connection in case the Producer is disconnected for some reason.
+During the reconnection it continues to store the messages in a local-list.
+The user will receive back the confirmed or un-confirmed messages.
+
+#### Trace sent and received messages
+Reliable Producer keeps in memory each sent message and remove from the memory when the message is confirmed or goes in timout.
+`ConfirmationHandler` receives the messages  back with the status.
+`confirmation.Status` can have different values, but in general `ConfirmationStatus.Confirmed` means the messages
+is stored on the server other status means that there was a problem with the message/messages.
+```csharp
+ConfirmationHandler = confirmation =>
+{                    
+    if (confirmation.Status == ConfirmationStatus.Confirmed)
+    {
+
+        // OK
+    }
+    else
+    {
+        // Some problem
+    }
+}
+```
+#### Invalidate messages
+If the client doesn't receive a confirmation within 2 seconds Reliable Producer removes the message from the internal messages cache.
+The user will receive `ConfirmationStatus.TimeoutError` in the `ConfirmationHandler`.
+
+#### Handle the metadata Update
+If the streams changes the topology (ex:Stream deleted or add/remove follower), the client receives an `MetadataUpdate` event.
+Reliable Producer detects the event and tries to reconnect the producer if the stream still exist else closes the producer.
+#### Send API
+Reliable Producer implements two `send(..)`
+- `Send(Message message)` // standard
+- `Send(List<Message> messages, CompressionType compressionType)` //sub-batching with compression
+
+### Reconnection Strategy 
+By default Reliable Producer uses an `BackOffReconnectStrategy` to reconnect the client.
+You can customize the behaviour implementing the `IReconnectStrategy` interface:
+```csharp
+void WhenDisconnected(out bool reconnect);
+void WhenConnected();
+```
+with `reconnect` you can decide when reconnect the producer.
+
+You can use it:
+```csharp
+var p = await ReliableProducer.CreateReliableProducer(new ReliableProducerConfig()
+{
+...
+ReconnectStrategy = MyReconnectStrategy
+```
+
+#### Examples
+See the directory [Examples/Reliable](./Examples/Reliable)
+
 
 ### Build from source
 Build: