It is possible to issue two SYN_STREAM packets in reversed order

[direvius]

As stated in SPDY Protocol - Draft 3.1:

The stream-id MUST increase with each new stream.

But using goroutines it is possible to run into a situation where SYN_STREAM #3 being issued before SYN_STREAM #1:

[SPDY DEBUG] 2015/10/12 20:16:01 Sending SYN_STREAM:
    Frame: SYN_STREAM, Stream #3, Flags: FIN
...
[SPDY DEBUG] 2015/10/12 20:16:01 Sending SYN_STREAM:
    Frame: SYN_STREAM, Stream #1, Flags: FIN

[cpg]

Good catch.

[cpg]

I have been thinking about this. This basically means that streams have to be numbered at the very last moment, not when allocated, after they are sending things.

Do you have a simple test case you can share to further help in tracking down a good solution for this?

[direvius]

Yes, just issue several parallel requests using goroutines: https://gist.github.com/direvius/761c55acc916c76fac04
You'll probably need to run it several times to catch it. On my mac it fails in about 70% of all cases.