QML/Qt3D Basic example of GeometryRenderer use

I'm looking for a basic example of how to set up an Entity with a GeometryRenderer in QML.

The code I'm using right now is shown below. If I replace geometryRenderer by a CuboidMesh then a blank cube is shown. The goal is to display a simple triangle. Is my GeometryRenderer declaration correct ?

Entity{

    Material{
      id: simpleMaterial 
      effect: SimpleEffect{}
    }

    GeometryRenderer{
      id: geometryRenderer

    instanceCount: 1
    primitiveType: GeometryRenderer.Triangles
    geometry: Geometry{

            Attribute{
                attributeType: Attribute.VertexAttribute
                vertexBaseType: Attribute.Float
                vertexSize: 3
                byteOffset: 0
                byteStride: 3 * 4
                count: 3

                buffer : Buffer{
                    id: vertexBuffer
                    type: Buffer.VertexBuffer
                    data: [ 0.0, 0.0, 0.0,
                            0.0, 10.0, 0.0,
                            10.0, 10.0, 0.0]
                }
            }
        }
    }

components: [simpleMaterial, geometryRenderer]
}