hah. after two hours of debugging, i have discovered it is spooky HPACK action at a distance.
i was sending too many headers.
[
":scheme": "https",
":authority": authority.domain,
":status": "\(status)"
]
for some reason :scheme and :authority causes NIO, or curl, or firefox, or all three, to ignore the headers frame. then when NIO sends rstStream to terminate the stream, curl/firefox gets confused and thinks the stream was reset for no reason.
moral of the story: it’s always HPACKHeaders’ fault!
in all seriousness though, this type could really benefit from a builder API. nobody should be encoding pseudo-headers manually! it’s just asking for trouble…
// one day...
let headers:HPACKHeaders = .server(status: 200)
{
$0["content-type"] = "\(contentType)"
$0["content-length"] = "\(length)"
$0["etag"] = "\"\(hash)\""
}