public static IConfigurationBuilder AddAwsS3(this IConfigurationBuilder builder,
                                              string bucket,
                                              string key,
                                              bool optional   = false,
                                              TimeSpan?period = default,
                                              string prefix   = default,
                                              Func <AsyncLoaderExceptionContext, Task> onException = default)
 {
     return(builder.AddAwsS3(() => new AmazonS3Client(), new GetObjectRequest
     {
         BucketName = bucket,
         Key = key
     }, optional, period, prefix, onException));
 }