/**
* Read a SortedMap as a sequence of key/value pairs encoded as variable-byte integers (value are gap-encoded). Use the framework to look up each Object by it's ordinals.
*/
@Override
public <K, V> SortedMap<K, V> deserializeSortedMap(FastBlobDeserializationRecord rec, String fieldName, NFTypeSerializer<K> keySerializer, NFTypeSerializer<V> valueSerializer) {
ByteData byteData = rec.getByteData();
long fieldPosition = rec.getPosition(fieldName);
if(fieldPosition == -1 || VarInt.readVNull(byteData, fieldPosition))
return null;