change readStop to private function

[hotyhuang]

To fix issue: spdy-http2/node-spdy#369
Issue reproduce POC: https://github.com/hotyhuang/SSEexample

I found out that this issue with SSE is caused by recent commit in Nodejs: nodejs/node@138eb32
I personally is not familiar with spdy code, just tried out this solution, and looks like it's working perfectly with node v10 ~ v12.

[aphix]

Friendly ping: @indutny @daviddias

Cheers =)

[aphix]

I'm still able to repro the issue (spdy-http2/node-spdy#369) after applying this patch locally, will put together a repro and work on a fix this weekend if not later today. @hotyhuang

FWIW, I didn't try your repro repo, but was able to get it to happen in 12.18.3 by spamming ctrl+shift+r in Firefox with a listening server.

I believe this is a graph of what happened (I did capture a profile, but I can't share it publicly, so let me know if there's a private way to pass it along to one of the maintainers):

As far as I've tracked it thus far, following a RST, this callback in spdy-transport:

https://github.com/spdy-http2/spdy-transport/blob/master/lib/spdy-transport/stream.js#L139

Is calling its callback twice in the _split function:

https://github.com/spdy-http2/spdy-transport/blob/master/lib/spdy-transport/stream.js#L237

And everything tears itself down afterward.

Also note: I'm NOT using req.push anywhere.

[hotyhuang]

@aphix Thank you for paying attention to this issue. This is occurred long back when node version was v12.18.1. I am not sure if the updates changed anything.

By the time I was looking into this code, there seems a lot more logics behind the scenes, rather than the twice callback. That's why I changed the stop func to be private, to get rid of duplicate call by other internal methods.

If you could figure this out it will be great help! But i would rather expect some response from the owner of this repo (since they will know how to fix it properly, and thanks for pinning their ids).