protected void prepare(Mailbox mbx, ZimbraQueryResultsImpl res, MailboxIndex mbidx, int chunkSize) {
protected void prepare(Mailbox mbx, ZimbraQueryResultsImpl res, MailboxIndex mbidx, SearchParams params, int chunkSize) { mParams = params;
    protected void prepare(Mailbox mbx, ZimbraQueryResultsImpl res, MailboxIndex mbidx, int chunkSize) {    }