- Metal: when a layer has no drawable to give (it can take a second to
say so), don't ask again in the same frame for every pass to it.
- Swapchains other than the primary are created, resized and destroyed
between frames (Metal asserts it), and destroyed with the last
reference to them (ReleaseAssertLast, Metal and Vulkan).
- BindFramebufferSamplesAsTexture asserts it isn't given a swapchain,
like BindFramebufferAsTexture.
- An offscreen Metal swapchain can't be resized, asserted.
- VulkanRenderManager asserts that no additional swapchain outlives it.
- Native_RemoveOutputAndWait asserts it isn't called on the thread that
handles the requests, where it would always time out.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
