使用D3.xml绘制树布局

In d3.js, I have seen the use of d3.JSON to use a JSON for building a tree layout. I have also worked with csv files, to first convert those in JSON by using d3.csv and d3.nest. But,while taking a XML data dource using d3.xml, can anyone suggest how to proceed for making a tree layout without converting xml data to JSON first?In d3.js, I have seen the use of d3.JSON to use