Basic Node HTTP/2 Push Server

chrome debug log

628408: HTTP2_SESSION
localhost:8443 (DIRECT)
Start Time: 2018-03-22 09:00:43.870

t=1298705 [st=0] +HTTP2_SESSION  [dt=?]
                  --> host = "localhost:8443"
                  --> proxy = "DIRECT"
t=1298705 [st=0]    HTTP2_SESSION_INITIALIZED
                    --> protocol = "h2"
                    --> source_dependency = 628407 (SOCKET)
t=1298705 [st=0]    HTTP2_SESSION_SEND_SETTINGS
                    --> settings = ["[id:1 (SETTINGS_HEADER_TABLE_SIZE) value:65536]","[id:3 (SETTINGS_MAX_CONCURRENT_STREAMS) value:1000]","[id:4 (SETTINGS_INITIAL_WINDOW_SIZE) value:6291456]"]
t=1298705 [st=0]    HTTP2_SESSION_UPDATE_RECV_WINDOW
                    --> delta = 15663105
                    --> window_size = 15728640
t=1298705 [st=0]    HTTP2_SESSION_SEND_WINDOW_UPDATE
                    --> delta = 15663105
                    --> stream_id = 0
t=1298705 [st=0]    HTTP2_SESSION_SEND_HEADERS
                    --> exclusive = true
                    --> fin = true
                    --> has_priority = true
                    --> :method: GET
                        :authority: localhost:8443
                        :scheme: https
                        :path: /robots.txt
                        user-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.181 Safari/537.36
                        accept: */*
                        accept-encoding: gzip, deflate, br
                        accept-language: fr-FR,fr;q=0.9,en-US;q=0.8,en;q=0.7
                    --> parent_stream_id = 0
                    --> source_dependency = 628404 (HTTP_STREAM_JOB)
                    --> stream_id = 1
                    --> weight = 220
t=1298705 [st=0]    HTTP2_SESSION_RECV_SETTINGS
t=1298705 [st=0]    HTTP2_SESSION_SEND_SETTINGS_ACK
t=1298705 [st=0]    HTTP2_SESSION_RECV_SETTINGS_ACK
t=1298706 [st=1]    HTTP2_SESSION_RECV_HEADERS
                    --> fin = false
                    --> :status: 200
                        content-type: text/html
                        date: Thu, 22 Mar 2018 08:00:43 GMT
                    --> stream_id = 1
t=1298706 [st=1]    HTTP2_SESSION_RECV_PUSH_PROMISE
                    --> :scheme: https
                        :authority: localhost:8443
                        :method: GET
                        :path: /index.css
                    --> id = 1
                    --> promised_stream_id = 2
t=1298706 [st=1]    HTTP2_STREAM_SEND_PRIORITY
                    --> exclusive = true
                    --> parent_stream_id = 1
                    --> stream_id = 2
                    --> weight = 110
t=1298706 [st=1]    HTTP2_SESSION_RECV_HEADERS
                    --> fin = false
                    --> :status: 200
                        content-type: text/css
                        date: Thu, 22 Mar 2018 08:00:43 GMT
                    --> stream_id = 2
t=1298706 [st=1]    HTTP2_SESSION_RECV_DATA
                    --> fin = false
                    --> size = 61
                    --> stream_id = 1
t=1298706 [st=1]    HTTP2_SESSION_UPDATE_RECV_WINDOW
                    --> delta = -61
                    --> window_size = 15728579
t=1298706 [st=1]    HTTP2_SESSION_RECV_DATA
                    --> fin = false
                    --> size = 16
                    --> stream_id = 2
t=1298706 [st=1]    HTTP2_SESSION_UPDATE_RECV_WINDOW
                    --> delta = -16
                    --> window_size = 15728563
t=1298706 [st=1]    HTTP2_SESSION_RECV_DATA
                    --> fin = true
                    --> size = 0
                    --> stream_id = 1
t=1298706 [st=1]    HTTP2_SESSION_UPDATE_RECV_WINDOW
                    --> delta = 61
                    --> window_size = 15728624
t=1298707 [st=2]    HTTP2_SESSION_RECV_DATA
                    --> fin = true
                    --> size = 0
                    --> stream_id = 2

server.js

const http2 = require("http2");
const fs = require("fs");

const server = http2.createSecureServer({
  key: fs.readFileSync("certs/localhost-privkey.pem"),
  cert: fs.readFileSync("certs/localhost-cert.pem")
});
server.on("error", err => console.error(err));

server.on("stream", (stream, headers) => {
  stream.respond({
    "content-type": "text/html",
    ":status": 200
  });
  stream.pushStream({ ":path": "/index.css" }, (err, pushStream, headers) => {
    if (err) throw err;
    pushStream.respond({
      "content-type": "text/css",
      ":status": 200
    });
    pushStream.end("h1 {color: red;}");
  });
  stream.end(
    `<h1>Hello World</h1><link rel="stylesheet" href="/index.css" crossorigin>`
  );
});

server.listen(8443);