Hi all，
We are now using kafka 0.9.0 in our product enviroment, and we add one
broker to the cluster，and execute reassign partitions between all brokers，we
find our network card and disk io is very high.
and I know KIP-73 has resolved this problem, but I wonder can I merge it to my
kafka 0.9.0 directly, because I have two doubts as below.
1.https://github.com/apache/kafka/pull/1776
<https://github.com/apache/kafka/pull/1776> is created compared with trunk,
kafka 0.9.0 is diff to trunk.
2.because of the diff of kafka 0.9.0 and trunk, there may be some
bugfixs that associated with this pr, how can I avoid this risk.
Any suggestion is appreciated，thanks in advance.
