hollow cylinder 3d model

The object is a cylinder. The cylinder is 20 mm in outer diameter and 30 mm tall. In the center of the cylinder, create a straight cylindrical hole that is 8.05 mm in diameter. This hole must go all the way through the cylinder from top to bottom. Inside this hole, create a male key. The male key must be a rectangular protrusion that is 3 mm wide and 3 mm tall. The male key must run the full 30 mm height of the cylinder. The male key must be physically attached to the inner wall of the 8.05 mm hole. The male key must not be a separate piece. The male key must be part of the same solid body as the cylinder. The final result must be one single watertight 3D object