perf: zero-copy receive in ConvertToMessage

Reference envelope.Body directly instead of copying via ToArray(). Safe because the
body is deserialized synchronously within the awaited subscriber dispatch before the
handler returns, per the handler-scoped IMessage.Data validity contract.

Author: niemyjski

src/Foundatio.RabbitMQ/Messaging/RabbitMQMessageBus.cs

@@ -472,7 +472,12 @@ await _publisherReady.WaitAsync(cancellationToken)
 
     protected virtual IMessage ConvertToMessage(BasicDeliverEventArgs envelope)
     {
-        var message = new Message(envelope.Body.ToArray(), DeserializeMessageBody)
+        // Zero-copy: envelope.Body is a pooled buffer that RabbitMQ.Client reclaims once OnMessageAsync
+        // returns. Referencing it without copying is safe because the body is deserialized synchronously
+        // within the awaited SendMessageToSubscribersAsync dispatch, before the handler returns. Per the
+        // IMessage.Data contract, the buffer is only valid for the duration of handling; consumers that
+        // retain the raw payload beyond the handler must copy it via ToArray().
+        var message = new Message(envelope.Body, DeserializeMessageBody)
         {
             Type = envelope.BasicProperties.Type,
             ClrType = GetMappedMessageType(envelope.BasicProperties.Type),