message: make begin/end_frame public
diff: @@ -353,7 +353,10 @@ impl GraphicsContext {
  self.fcx.as_mut().map(|fcx| &mut fcx.cmd)
  }
  - pub(crate) fn begin_frame(&mut self) -> GameResult {
  + /// Begins a new frame.
  + ///
  + /// The only situation you need to call this in is when you are rolling your own event loop.
  + pub fn begin_frame(&mut self) -> GameResult {
  if self.fcx.is_some() {
  return Err(GameError::RenderError(String::from(
  "cannot begin a new frame while another frame is still in progress; call end_frame first",
  @@ -384,7 +387,10 @@ impl GraphicsContext {
  Ok(())
  }
  - pub(crate) fn end_frame(&mut self) -> GameResult {
  + /// Ends the current frame.
  + ///
  + /// The only situation you need to call this in is when you are rolling your own event loop.
  + pub fn end_frame(&mut self) -> GameResult {
  if let Some(mut fcx) = self.fcx.take() {
  let mut present_pass = fcx.cmd.begin_render_pass(&wgpu::RenderPassDescriptor {
  label: None,
  