Interesting question, for what purpose would you use this?
For now you could use a Clip with a 'Blank' source, and change it's duration to the time you desire.
Then change the autopilot setting of that Blank Clip to trigger the Clip you need.
I've been doing that for years (used to make a solid color with alpha only before the blank clips) but it clutters comps for no reason and makes the process more complicated as you need to create an extra column.
Having the ability to delay the trigger of a clip in a column would make theatrical compositions much easier.