IronPigeon.Relay.Controllers.InboxController.PurgeExpiredAsync C# (CSharp) Method

        public static async Task PurgeExpiredAsync(CloudBlobContainer inboxContainer)
        {
            Requires.NotNull(inboxContainer, "inboxContainer");

            var deleteBlobsExpiringBefore = DateTime.UtcNow;
            int purgedBlobCount = 0;
            var searchExpiredBlobs = new TransformManyBlock<CloudBlobContainer, ICloudBlob>(
                async c =>
                {
                    try
                    {
                        var results = await c.ListBlobsSegmentedAsync(
                            string.Empty,
                            useFlatBlobListing: true,
                            pageSize: 50,
                            details: BlobListingDetails.Metadata,
                            options: new BlobRequestOptions(),
                            operationContext: null);
                        return from blob in results.OfType<ICloudBlob>()
                               let expires = DateTime.Parse(blob.Metadata[ExpirationDateMetadataKey])
                               where expires < deleteBlobsExpiringBefore
                               select blob;
                    }
                    catch (StorageException ex)
                    {
                        var webException = ex.InnerException as WebException;
                        if (webException != null)
                        {
                            var httpResponse = (HttpWebResponse)webException.Response;
                            if (httpResponse.StatusCode == HttpStatusCode.NotFound)
                            {
                                // it's legit that some tests never created the container to begin with.
                                return Enumerable.Empty<ICloudBlob>();
                            }
                        }

                        throw;
                    }
                },
                new ExecutionDataflowBlockOptions
                {
                    BoundedCapacity = 4,
                });
            var deleteBlobBlock = new ActionBlock<ICloudBlob>(
                blob =>
                {
                    Interlocked.Increment(ref purgedBlobCount);
                    return blob.DeleteAsync();
                },
                new ExecutionDataflowBlockOptions
                {
                    MaxDegreeOfParallelism = 4,
                    BoundedCapacity = 100,
                });

            searchExpiredBlobs.LinkTo(deleteBlobBlock, new DataflowLinkOptions { PropagateCompletion = true });

            searchExpiredBlobs.Post(inboxContainer);
            searchExpiredBlobs.Complete();
            await deleteBlobBlock.Completion;
        }