The LlamaLoggerClient sends entries asynchronously so your application performance is not impacted. Because of this, it's possible for your application to exit prior to all entries being flushed from the queue. You can ensure your entries have a chance to be sent by calling the FlushQueue() method or disposing of the LlamaLoggerClient.
LlamaLoggerClient client = new LlamaLoggerClient(apikey, version);
...
client.FlushQueue(10000); //Allow up to 10 seconds for the queue to be flushed
LlamaLoggerClient client = new LlamaLoggerClient(apikey, version);
...
client.Dispose();