Is there a better way for knowing when the last spreadsheet row has been passed to my custom API?

I have created a custom WEBADI integrator, per my customers specifications, which includes a custom API for uploading records into the two AP Interface tables. Everything is working well enough, but I have not figured out a good way to know when the end of the spreadsheet rows have been reached. The integrator is calling my custom API and passing it each row of the spreadsheet. I am processing all of the rows but am not knowing when the last spreadsheet row is reached. The best idea I have come up with is forcing the last row of the spreadsheet