System should display alert and cancel the transaction if user trying upload excel file and system take longer than thresh-hold time to load the file data.

Not able to figure out a OOTB solution. Analysis is in Progress. Tried this kind of solution below , when the time is elapsed then we can put a break statement. But while the thread of execution is on parsing of the file or on attaching the data to pyAttachStream of Data-Work-Attach-File class. How can we bring the point of execution to this while loop. More- Over I am having doubt on how to determine where the time is taken more, is that the parsing time or the attaching time to clipboard.