What you are looking for is linearization. See which basically says iText has no native support for this and they currently don't have any future plans for it. From that page: Linearization doesn't make any sense for dynamically created files or for files that need to be served to a mobile device. It would be 'Slow Web View'.

Up until now, we've had several users asking for linearized PDFs, but once they fully understood that linearization would slow down the download process rather than make it faster, they decided against it. That's why we never put Linearization on our roadmap. Of course: if somebody wants to sponsor the development: you're always welcome to do so.

Qpdf linearization of PDF file with pages merged using iText's PDFStamper results in missing pages #33. Maxwell Sv Software Programs. Read PDF Metadata flag 'fast web view'. Hello I need to read the meta-data flag 'fast web view' of a PDF document. With iText I can. The linearization.