from bug 664344 - a description of receiving first-frag, ping, last-frag causing multiple pongs in response along with general wonkiness.
problem is in removing the ping from the fragment frame, length reset to 0 before a calculation was made.
1 line fix.
Created attachment 550099 [details] [diff] [review]
This fixes tests 3.6 and 3.7 from https://github.com/oberstet/Autobahn