In very high latency situations new connections are too expensive. Say you have 300msecs packet latency, which is common in mobile. That means in worst case, th

In very high latency situations new connections are too expensive. Say you have 300msecs packet latency, which is common in mobile. That means in worst case, that XHR will take at least one second just to the DNS lookup and establish the TCP connection to start downloading the file. It's not the volts, it's the amps that kill you. So to speak.