ReportingProgress.cs

public async Task<int> ProcessMessagesAsync(List<string> messages, IProgress<int> progress)
{
    int totalCount = messages.Count;
    int processCount = await Task.Run<int>(() =>
    {
        int tempCount = 0;
        foreach (var message in messages)
        {
            Console.WriteLine(message);
            if (progress != null)
            {
                progress.Report((tempCount * 100 / totalCount));
            }
            tempCount++;
        }

        return tempCount;
    });
    return processCount;
}