MongoDB.Driver.Document.CopyTo C# (CSharp) Method

        public void CopyTo(Document dest)
        {
            foreach (String key in orderedKeys) {
                dest[key] = this[key];
            }
        }

 public void TestCopyToCopiesAndOverwritesKeys()
 {
     Document d = new Document();
     Document dest = new Document();
     dest["two"] = 200;
     d["one"] = 1;
     d.Add("two", 2);
     d["three"] = 3;
     d.CopyTo(dest);
     Assert.AreEqual(2, dest["two"]);
 }