kafka-1091; full topic list can be read from metadata cache in the broker instead of ZK; patched by Jun Rao; reviewed by Joel Koshy, Guozhang Wang, Swapnil Ghike, and Neha Narkhede
kafka-1090; testPipelinedRequestOrdering has transient failures; patched by Jun Rao; reviewed by Joel Koshy, Guozhang Wang, and Neha Narkhede