private Integer _unsafe_add(Record r) {
        Integer newId = data.atomicNextAvailableRecordId.getAndIncrement();
        data.records.put(newId, r);

        return newId;
    }
private Integer _unsafe_add ( Record r ) { Integer newId = data . atomicNextAvailableRecordId . getAndIncrement ( ) ; data . records . put ( newId , r ) ; return newId ; }
Adds the record in the dataset without updating the Meta. The add method
returns the id of the new record.

@param r
@return