As per our understandings, you need to process multiple files for conversion and want to measure progress of each file. Please confirm if our assumptions are correct so that we can proceed further to assist you accordingly.
We regret to share that your requirement to track progress for multiple documents may not be fulfilled at the moment. Please note that the functionality is ported from Aspose.PDF for .NET and .NET API does not provide this feature. We will further investigate the feasibility of this feature and let you know as soon as we have some updates.
Thanks all the same.