S3 IO library: enable DNS resolver cache with 1 second expiration default; add configuration parameters to set DNS resolver cache size, expiration time, and resolver type.
S3 IO library: enable DNS resolver cache with 1 second expiration default; add configuration parameters to set DNS resolver cache size, expiration time, and resolver type.

quantcast/qfs,quantcast/qfs,quantcast/qfs,quantcast/qfs,quantcast/qfs,quantcast/qfs,quantcast/qfs,quantcast/qfs