Simplest way to convert an array into a set

[Matt]

Obviously, there is no "set" object in D, but I was wondering 
what the quickest way to remove duplicates from an array would 
be. I was convinced I'd seen a "unique" method somewhere, but 
I've looked through the documentation for std.array, 
std.algorithm AND std.range, and I've either missed it, or my 
memory is playing tricks on me. That, or I'm looking in the wrong 
place entirely, of course