How do I chunk-transfer a large-ish PDF with Echo?

[eslksw]

AFAIK, there are three ways to serve PDFs:

• Send PDF bytes, which is suboptimal because you have to load the PDF into memory.
• Serve from file (what I am currently doing), also potentially suboptimal because one has to implement cleanup routines.
• Stream PDF bytes, which IMO is probably the strategy with least drawbacks.

However, I am not familiar with how to implement PDF streaming using Echo. Any hints on how I could achieve this?

[aldas]

if these are not in memory created probably standard library sendfile can help

this needs to be adjusted to Echo interface

		w.Header().Set("Content-Disposition", `attachment; filename="report.pdf"`)
		http.ServeFile(w, r, "./files/report.pdf")