message: PostProcessManager: repair Vulkan by re-ordering commands.
  The suzanne Vulkan demo was asserting because `setViewportScissor` can
  only be called within a render pass, which means that
  `MaterialInstance::use` can only be called within a render pass.
  We probably need a better way to enforce these rules...
diff: @@ -189,7 +189,6 @@ FrameGraphId<FrameGraphTexture> PostProcessManager::toneMapping(FrameGraph& fg,
  mPostProcessUb.setUniform(offsetof(PostProcessingUib, time), fraction);
  pInstance->commit(driver);
  - pInstance->use(driver);
  PipelineState pipeline;
  pipeline.rasterState = mTonemapping.getMaterial()->getRasterState();
  @@ -200,6 +199,7 @@ FrameGraphId<FrameGraphTexture> PostProcessManager::toneMapping(FrameGraph& fg,
  auto const& target = resources.getRenderTarget(data.rt);
  driver.beginRenderPass(target.target, target.params);
  + pInstance->use(driver);
  driver.draw(pipeline, fullScreenRenderPrimitive);
  driver.endRenderPass();
  });
  