How to cancel a long-running request?

[harvister]

if I set context.request.body equal to a Deno.Reader in order to stream a long-running response, how do I just cancel it half way through?

I'm looking for something like context.cancel()

I'm running into a problem where a fetch call from a browser client will not fail until either the full request body is read, or the server is stopped. I want to be able to tell the client to fail the request without having to read the remaining request body, which I'm also reading as a Deno.Reader. If the request body is a 1 GB file, I do not want to have to read all of it just so the client will fail the fetch request.