DO NOT USE THIS INSTANCE FOR LIVE DATA!!!!
https://github.com/apache/tez/blob/master/tez-runtime-library/src/main/java/org/apache/tez/runtime/library/common/shuffle/orderedgrouped/MergeManager.java#L1304
Passed on codec is not used in TezMerger.
TEZ-4295 Could not decompress data. Buffer length is too small.
TEZ-4234 Compressor can cause IllegalArgumentException in Buffer.limit where limit exceeds capacity