What is really the use of the :clock-in property in org-capture-templates ?

Hi Guys,

I was trying to make use of :clock-in property in org-capture-templates variable. I thought what it does is it clocks in the item after the capture.
But what it does for me is, it clocks in the item but immediately clocks it out, leaving a 0 minute clock entry. What is the intended use of the property?