public static CompactionDescriptor getCompaction(Cell kv) throws IOException {
    return isCompactionMarker(kv) ? CompactionDescriptor.parseFrom(CellUtil.cloneValue(kv)) : null;
  }
Deserialized and returns a CompactionDescriptor is the KeyValue contains one.
@param kv the key value
@return deserialized CompactionDescriptor or null.
hbase-server/src/main/java/org/apache/hadoop/hbase/wal/WALEdit.java