When using http2 in okhttp, why multi requests to the same host didn't use just one connectoin

Question

I would like to test okhttp's http2 function. And I make multi requsts to same host in async style. But, I found that, it involved multi connections, since the protocol is h2, It should use just one connection, right? The code is below. Ah, I'm using okhttp2.5

public class Performance {
    private final OkHttpClient client = new OkHttpClient();
    private final Dispatcher dispatcher = new Dispatcher();
    private final int times = 20;

    public Performance(){
        dispatcher.setMaxRequestsPerHost(2);
        client.setDispatcher(dispatcher);

        // Configure the sslContext
        // MySSLSocketFactory mySSLSocketFactory = new MySSLSocketFactory();
        // client.setSslSocketFactory(mySSLSocketFactory);
        // client.setHostnameVerifier(new HostnameVerifier() {
        //     public boolean verify(String s, SSLSession sslSession) {
        //         return true;
        //     }
        // });
    }
    public void run()throws Exception{
        for(int i=0; i<times; i++) {
            Request request = new Request.Builder()
                .url("https://http2bin.org/delay/1")
                .build();
            client.newCall(request).enqueue(new Callback() {
                public void onFailure(Request request, IOException e) {
                    e.printStackTrace();
                }

                public void onResponse(Response response) throws IOException {
                    System.out.println(response.headers().get("OkHttp-Selected-Protocol"));
                }
            });
        }
    }
    public static void main(String[] args)throws Exception{
        Performance performance = new Performance();
        performance.run();
    }
}

Answer 1

There's a bug in OkHttp where multiple simultaneous requests each create their own socket connection, rather than coordinating a shared connection. This only happens when the connections are created simultaneously. Work around by yielding 500ms before the 2nd connection.