protected abstract void prepare(Mailbox mbx, ZimbraQueryResultsImpl res, MailboxIndex mbidx, int chunkSize) throws IOException, ServiceException;
protected abstract void prepare(Mailbox mbx, ZimbraQueryResultsImpl res, MailboxIndex mbidx, SearchParams params, int chunkSize) throws IOException, ServiceException;
    protected abstract void prepare(Mailbox mbx, ZimbraQueryResultsImpl res, MailboxIndex mbidx, int chunkSize) throws IOException, ServiceException;