re #17 added cache feature for schema registry client.
re #17 added cache feature for schema registry client.

TrueCar/go_kafka_client,stealthly/go_kafka_client,yanzay/go_kafka_client,lazyval/go_kafka_mirror,mistsys/go_kafka_client,yanzay/go_kafka_client,iobeam/go_kafka_client,elodina/go_kafka_client,yanzay/go_kafka_client,elodina/go_kafka_client,lazyval/go_kafka_mirror,CrowdStrike/go_kafka_client,TrueCar/go_kafka_client,mistsys/go_kafka_client,CrowdStrike/go_kafka_client,iobeam/go_kafka_client,mistsys/go_kafka_client,stealthly/go_kafka_client,lazyval/go_kafka_mirror,iobeam/go_kafka_client,TrueCar/go_kafka_client