 Fix some prblems:     1.Handle the EsRejectedExecutionException[rejected execution (queue capacity 50)     2.Chinese string may be truncated.     3.Decrease the http.globalAgent.maxSockets to avoid too many     EsRejectedExecutionException
 Fix some prblems:
    1.Handle the EsRejectedExecutionException[rejected execution (queue capacity 50)
    2.Chinese string may be truncated.
    3.Decrease the http.globalAgent.maxSockets to avoid too many
    EsRejectedExecutionException

deseretbook/elasticsearch-exporter,xeeo/Elasticsearch-Exporter,ankon/Elasticsearch-Exporter,vtrifonov/Elasticsearch-Exporter,ankon/Elasticsearch-Exporter,vtrifonov/Elasticsearch-Exporter,mallocator/Elasticsearch-Exporter,deseretbook/elasticsearch-exporter,xeeo/Elasticsearch-Exporter,mallocator/Elasticsearch-Exporter