Added StopConsuming documentation.

Author: Anton Vorontsov

docs/message-consumption.md

@@ -33,7 +33,7 @@ You can register `IHostedService` and inject an instance of `IQueueService` into
 services.AddSingleton<IHostedService, ConsumingService>();
 ```
 
-And then simply call `StartConsuming` so a consumer can work in the background.
+Then simply call `StartConsuming` so a consumer can work in the background. There is also an option which allows you to stop consuming messages - method `StopConsuming` which you can use any time you want to pause a message consumption for any reason.
 
 ```c#
 public class ConsumingService : IHostedService
@@ -59,6 +59,7 @@ public class ConsumingService : IHostedService
     public Task StopAsync(CancellationToken cancellationToken)
     {
         _logger.LogInformation("Stopping consuming.");
+        _queueService.StopConsuming();
         return Task.CompletedTask;
     }
 }

src/RabbitMQ.Client.Core.DependencyInjection/Services/QueueService.cs

@@ -33,7 +33,7 @@ public sealed class QueueService : IQueueService, IDisposable
         readonly IEnumerable<RabbitMqExchange> _exchanges;
         readonly ILogger<QueueService> _logger;
 
-        IEnumerable<string> _consumerTags;
+        IEnumerable<string> _consumerTags = new List<string>();
         bool _consumingStarted;
         readonly object _lock = new object();