There is no real point in first requiring all data to be loaded into a big array and then splitting this big array into smaller arrays and then feeding them to `update`. The idea is that you request from PDF.js smaller chunks. Because then PDF.js can optimize. For example, use HTTP range requests to load from the server data in chunks. Maybe this is premature optimization and we should just request the whole deal from PDF.js and compute on that, but then you just pass it to `hash.update`. The best would be that you would benchmark and see how it behaves.