Adding RowsPerData to queryStream

I currently testing using the queryStream-Method to handle large data from our Database.

Because you set every row on the data-Event of the stream this is extremely slow and unusable. I wonder why this isn't a parameter. All node-Stream-Functions allow you to definie sizes of buffer.

I would suggest to add a paramter like:

queryStream(String sql, [Object bindParams], [Object options], [Number RowsPerData]);

Start at the queryStream entry point and trace how database rows are delivered through the stream's data events. Compare the proposed RowsPerData option with the existing queryStream signature and Node.js stream buffering behavior; the work is done when row delivery can be configured in groups for large queries and the resulting behavior is covered by appropriate tests.