Minor Description
Looking at https://github.com/prestodb/presto/blob/master/presto-hive/src/main/java/com/facebook/presto/hive/s3/PrestoS3FileSystem.java, they've done some interesting things: configurable connection timeouts and, retry options, statistics to count exceptions caught/re-opened, and more
review them, if there is good stuff there, add it to S3a