How to implement batch processing of messages in RabbitMQ?

In RabbitMQ, there are several approaches for batch message processing:

1. Prefetch count — set the prefetchCount parameter in BasicQos to receive multiple messages at once and process them together.

2. Buffering messages in code — accumulate messages in a list upon receipt and process them in batches, for example, every N messages or after a timeout.

Example in C# using RabbitMQ.Client:

var factory = new ConnectionFactory() { HostName = "localhost" };
using var connection = factory.CreateConnection();
using var channel = connection.CreateModel();

channel.BasicQos(0, 10, false); // receive 10 messages at a time

var consumer = new EventingBasicConsumer(channel);
var batch = new List<BasicDeliverEventArgs>();

consumer.Received += (model, ea) => {
    batch.Add(ea);
    if (batch.Count >= 10) {
        // Process batch of messages
        foreach (var msg in batch) {
            var body = msg.Body.ToArray();
            // processing
            channel.BasicAck(msg.DeliveryTag, false);
        }
        batch.Clear();
    }
};

channel.BasicConsume(queue: "myQueue", autoAck: false, consumer: consumer);

// You can add a timer to process incomplete batch after some time

This approach improves performance through batch processing and reduces overhead on message acknowledgments.