ParallelForEachAsync hangs when I update Microsoft.Bcl.AsyncInterfaces from 1.0.0.0 to 5.0.0.0

[kevinlcobb]

This code/app has been in place for years. Updated the Microsoft.Bcl.AsyncInterfaces from 1.0.0.0 to 5.0.0.0 and the app hangs in ParallelForEachAsync call.

var results = new ConcurrentBag<RowResult>(); await plogs.ParallelForEachAsync(async plog => { var response = await ProcessRow(plog.Item1, plog.Item2, fileUploadHistoryId, url, user, bankNo, companyNo, log); results.Add(response); }, maxDegreeOfParallelism: MaxDop).ConfigureAwait(false);

Break points in the ProcessRow method and it never gets there.