There is a known problem with SSRS Rendering, which is that when rendering PDFs a Content-Disposition: attachment; ...
header is sent which forces the file to download rather than open inline (here's an SO thread about it from 2009).
I am wondering if this can be worked around to make the PDF open in the browser by using a Rendering Extension in SSRS. I found an example Rendering Extension in C#, here: https://blogs.technet.microsoft.com/johannh/2017/07/14/creating-and-debugging-a-ssrs-custom-rendering-extension/
However, that code appears to only output a stream. Is it possible to somehow send headers before the stream is sent and therefore override the Content-Disposition
header that is usually sent?