private void allocateMultiple(MemoryBuffer[] dest, int size) {
      if (allocator != null) {
        allocator.allocateMultiple(dest, size, bufferFactory, isStopped);
      } else {
        bufferManager.getAllocator().allocateMultiple(dest, size, bufferFactory);
      }
    }
For !doesSourceHaveIncludes case, stores global column IDs to verify writer columns.
For doesSourceHaveIncludes case, stores source column IDs used to map things.
llap-server/src/java/org/apache/hadoop/hive/llap/io/encoded/SerDeEncodedDataReader.java