I am not sure whether the serialize function is working properly (the first example works, the second does not, because instead of tabs I get commas, and there is no way to specify to add the header)
<csv>
<record>
<a>f</a>
<b>f</b>
<c>f</c>
<d>f</d>
<e>f</e>
<f>f</f>
</record>
</csv> => csv:serialize(map{"header":"yes", "separator": " "})
return
<csv>
<record>
<a>f</a>
<b>f</b>
<c>f</c>
<d>f</d>
<e>f</e>
<f>f</f>
</record>
</csv> => serialize(map{"method":"csv", "item-separator": " "})