This is a mapreduce/spark output committer optimized for
performance and correctness on Azure ADLS Gen 2 storage
(via the abfs connector) and Google Cloud Storage
(via the external gcs connector library).
* It is safe to use with HDFS, however it has not been optimized
for that use.
* It is *not* safe for use with S3, and will fail if an attempt
is made to do so.
Contributed by Steve Loughran
Change-Id: I6f3502e79c578b9fd1a8c1485f826784b5421fca
7328c34ba5