[Cake] Upstream submission of dual-mode fairness patch

[Jonathan Morton]

> On 4 Mar, 2019, at 4:55 am, Georgios Amanakis <gamanakis at gmail.com> wrote:
> 
> …the fairness logic wouldn't account for that "ingress traffic" and would yield fairer results.

Well there we have a quandary, since presently it enforces fairness of *load* on the bottleneck link, but the change would alter that to fairness of *delivered* traffic.  The current setup is arguably more robust against adversarial traffic, don't you think?

 - Jonathan Morton