private Object uncheckedGetField(int fieldID) {
    if (fieldInited[fieldID]) {
      return fields[fieldID].getObject();
    }
    fieldInited[fieldID] = true;

    int fieldByteBegin = startPosition[fieldID];
    int fieldLength = startPosition[fieldID + 1] - startPosition[fieldID] - 1;
    if (isNull(oi.getNullSequence(), bytes, fieldByteBegin, fieldLength)) {
      fields[fieldID].setNull();
    } else {
      fields[fieldID].init(bytes, fieldByteBegin, fieldLength);
    }
    return fields[fieldID].getObject();
  }
Get the field out of the row without checking parsed. This is called by
both getField and getFieldsAsList.

@param fieldID
         The id of the field starting from 0.
@param nullSequence
         The sequence representing NULL value.
@return The value of the field
serde/src/java/org/apache/hadoop/hive/serde2/lazy/LazyStruct.java