Currently saving a modified PDF document may fail *intermittently*, if it's triggered before the entire document has been downloaded.
When saving was originally added we only supported forms, and such PDF documents are usually small/simple enough for this issue to be difficult to trigger. However, with editing-support now available as well it's possible to modify much larger documents and this issue thus becomes easier to trigger.
One way to reproduce this issue *consistently* is to:
- Open http://localhost:8888/web/viewer.html?file=/test/pdfs/pdf.pdf#disableHistory=true&disableStream=true&disableAutoFetch=true
- Add an annotation on the first page, it doesn't matter what kind.
- Save the document.
- Open the resulting document, and notice that with the `master` branch the annotation is missing.