NetworkServiceFull.cs

internal async Task<T> RetryInner<T>(Func<Task<T>> func,
                                         int retryCount = 1,
                                         Func<Exception, int, Task> onRetry = null)
{
    var onRetryInner = new Func<Exception, int, Task>((e, i) =>
    {
        return Task.Factory.StartNew(() => {
#if DEBUG
            System.Diagnostics.Debug.WriteLine($"Retry #{i} due to exception '{(e.InnerException ?? e).Message}'");
#endif
        });
    });

    return await Policy.Handle<Exception>().RetryAsync(retryCount, onRetry ?? onRetryInner).ExecuteAsync<T>(func);
}

internal async Task<T> WaitAndRetryInner<T>(Func<Task<T>> func, Func<int, TimeSpan> sleepDurationProvider,
                                            int retryCount = 1,
                                            Func<Exception, TimeSpan, Task> onRetryAsync = null)
{
    var onRetryInner = new Func<Exception, TimeSpan, Task>((e, t) =>
    {
        return Task.Factory.StartNew(() => {
#if DEBUG
            System.Diagnostics.Debug.WriteLine($"Retrying in {t.ToString("g")} due to exception '{(e.InnerException ?? e).Message}'");
#endif
        });
    });

    return await Policy.Handle<Exception>().WaitAndRetryAsync(retryCount, sleepDurationProvider, onRetryAsync ?? onRetryInner).ExecuteAsync<T>(func);
}