- add async/sync support to LogStash::Search::ElasticSearch#histogram
- add async/sync support to LogStash::Search::ElasticSearch#histogram

Aloomaio/logstash-kafka,opentable/logstash-kafka,Aloomaio/logstash-kafka,joekiller/logstash-kafka,tinglinux/logstash-kafka,opentable/logstash-kafka,tinglinux/logstash-kafka,joekiller/logstash-kafka