I’ve made it up to 10x faster. By parsing Http Content-Length header. You can find the code here:
Comparison:
Original Library : 10-12 sec
Modified Version: 600 ms
Using Photon.
Hitting a public API with average response time of 300ms on Desktop (Same WiFi Connection)
Feel free to test and let me know if there is any issues.
PS. Proof of concept. Code needs clean up 