Do most (IE, FF, Safari, Chrome, Opera) make multiple HTTP Requests for a PDF file when displaying the PDF in a browser? I am working on an issue integrating with WebTrends
My thoughts are that you are spot on: your plug-in can not (and should not) split PDF's into requests.
I have a web application which serves PDF files from a request (a single request) and displays in a plug-in. It displays the entire PDF without getting any more information.
Also, if you are looking for a HTTP sniffer you could try Fiddler. I have found this useful during web site debugging.