Render Pipeline Descriptor
constructor(vertex: RenderPipelineDescriptor.VertexState, label: String? = null, layout: PipelineLayout? = null, primitive: RenderPipelineDescriptor.PrimitiveState = PrimitiveState(), depthStencil: RenderPipelineDescriptor.DepthStencilState? = null, fragment: RenderPipelineDescriptor.FragmentState? = null, multisample: RenderPipelineDescriptor.MultisampleState = MultisampleState())