How to log retries from Polly with ILoggerFactory

Question

Or: How to log from a static method.

From https://github.com/App-vNext/Polly you have examples like this one where a logger is magically available:

Policy
  .Timeout(30, onTimeout: (context, timespan, task) => 
    {
        logger.Warn($"{context.PolicyKey} at {context.ExecutionKey}: execution timed out after {timespan.TotalSeconds} seconds.");
    });

In my code I am using the new IHttpClientFactory pattern from dotnet core 2.1, and adding it like this in my Startup.cs ConfigureServices method:

    services.AddHttpClient<IMySuperHttpClient, MySuperHttpClient>()
        .AddPolicyHandler(MySuperHttpClient.GetRetryPolicy())
        .AddPolicyHandler(MySuperHttpClient.GetCircuitBreakerPolicy());

With the GetRetryPolicy being static and looking like this:

internal static IAsyncPolicy<HttpResponseMessage> GetRetryPolicy()
{
    return HttpPolicyExtensions
        .HandleTransientHttpError()
        .OrResult(msg => msg.StatusCode == System.Net.HttpStatusCode.NotFound)
        .WaitAndRetryAsync(
            retryCount: 4,
            sleepDurationProvider: retryAttempt => TimeSpan.FromSeconds(Math.Pow(2, retryAttempt)),
            onRetry: OnRetry);
}

Where the OnRetry method aswell have to be static:

private static void OnRetry(DelegateResult<HttpResponseMessage> delegateResult, TimeSpan timespan, Context context)
{
    // var logger = ??
    // logger.LogWarning($"API call failed blah blah.");
}

How can you access an ILoggerFactory here, if at all possible?