There was something off with the math for the ServiceCurves. The set value was 8
times too large and the returned one was 8 times too small.
This is now fixed in `class.go` and `class_linux.go` so the user can just set the rate in bit and
it will match the tc show output.
Testing and functionality for the use of HFSC has been implemented.
The use of service curves is implenented closely as to how they behave
with the TC implementation.
Automated checks and testing were succesful.
This patch adds ClassStatistics, a struct that represents the stats
of a class based on genric networking stats for netlink, to ClassAttrs.
The parsers for rtattrs in type of TCA_STATS and TCA_STATS2 are
introduced as well and the stats are appropriately parsed as a part
of ClassAttrs struct.
The practical tests for stats are not contained in this patch yet since
it requires the actual packet sending/receiving in the random timing,
which makes the tests complicated and flaky. Once we figure it out how
to test them in the proper way, they shall be added.
Signed-off-by: Taku Fukushima <taku@soracom.jp>
