I used the Geometry service to get a buffer of a polyline, polygon, etc.. and it worked great. My next task is to get a buffer line that is to seaward of land. For example, find a buffer line 100 yard from the coastline. I'll pass in a coastline polyline and a distance of 100 yards, hoping to get back a buffer line 100 yards from the coastline. What is the Geometry utility or APIs to use to accomplish this?