I used my own method to know the progress. May be not the best one but it works fine for me.:
var archive = SharpCompress.Archive.ArchiveFactory.Open(fileStream);
int totalFileCount = archive.Entries.Count();
int fileCount = 0;
int currentPercentage = 0;
foreach (var entry in archive.Entries)
{
///Your action
fileCount++;
currentPercentage = (fileCount * 100)/ totalFileCount;
//Update UI or Delegate etc.
}