message: SampleUtils: Flush the wire before getting preferred format
  This makes sure that the swapchain has been created on the server side
  and that the preferred swapchain format is correctly computed.
diff: // See the License for the specific language governing permissions and
  // limitations under the License.
  +#include "SampleUtils.h"
  +
  #include "common/Platform.h"
  #include "utils/BackendBinding.h"
  #include "wire/TerribleCommandBuffer.h"
  @@ -122,6 +124,7 @@ uint64_t GetSwapChainImplementation() {
  }
  nxt::TextureFormat GetPreferredSwapChainTextureFormat() {
  + DoFlush();
  return static_cast<nxt::TextureFormat>(binding->GetPreferredSwapChainTextureFormat());
  }
  