canvas.points memory observation

I am seeing memory double for the datashader process during the call

agg=csv.points(df,'x','y',ds.count('t'))

When the call finishes memory returns to the amount prior to the aggregate call.
I have not reviewed the code, but am wondering if the user should have control of the variable type used for the aggregation, or add a 'hint' if it can conserve memory. I'm speculating this is using a double or 64 bit integer, ideally an unsigned 'int' would be an option.