Importing an STL into my Grasshopper Code (in a C# solution)

I am writing a grasshopper component in C#. I am trying to load an STL file stored in my C# Solution.

            Rhino.FileIO.File3dm unitStoneDoc = Rhino.FileIO.File3dm.Read("/Assets/unitStone.stl");
            var objectOnDefaultLayer = unitStoneDoc.Objects.FindByLayer("Default")[0];
            // declare a brep representing the unit stone.
            Brep unitStone = objectOnDefaultLayer.Geometry as Brep;

I am not sure how File3dm know how to read an stl. At any rate, i am getting the error in Grasshopper:
1. Solution exception:The provided path is null, does not exist or cannot be accessed.
So it seems like it cannot find the file, and I am not sure the code knows what to do with it if it were to find it. Can Read handle relative paths like this?

Sorry the title may not have been clear. The question is not about importing geometry into a grasshopper definition but rather how to reference geometry stored in a the same C# project or solution.

you can embed a .3dm file as ressource and then read it as byte array, pass to file3dm.frombytearray and search for the needed geometry
https://developer.rhino3d.com/api/rhinocommon/rhino.fileio.file3dm/frombytearray

Thanks @Tom_P

Here is what I came up with to import geometry as a binary from the C# project using a Stream. I also had to include the file in the solution by going to Properties > Build Action > Embedded resource.

  protected override void SolveInstance(IGH_DataAccess DA)
       {
            File3dm file3dm;
            Mesh unitStone = null;
            using (Stream stream = Assembly.GetExecutingAssembly().GetManifestResourceStream("SteveJewelryToolbox.Assets.unitRoundStone.3dm"))
            {
                byte[] bytes;
                //read the stream as a byte array.
                using (var reader = new BinaryReader(stream))
                {
                    bytes = reader.ReadBytes((int)stream.Length);
                    file3dm = File3dm.FromByteArray(bytes);
                }
            }
            File3dmObject[] objectOnDefaultLayer = file3dm.Objects.FindByLayer("Layer1");
            unitStone = objectOnDefaultLayer[0].Geometry as Mesh;
...