message: Request memory with VK_MEMORY_PROPERTY_HOST_COHERENT_BIT enabled for model staging buffers.
  There is no guarantee in the spec on the order of the following memory types:
  VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_CACHED_BIT,
  VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT,
  which means we can't assume that the first memory type with VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT is going to be coherent.
diff: @@ -314,7 +314,7 @@ namespace vks
  // Vertex buffer
  VK_CHECK_RESULT(device->createBuffer(
  VK_BUFFER_USAGE_TRANSFER_SRC_BIT,
  - VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT,
  + VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT,
  &vertexStaging,
  vBufferSize,
  vertexBuffer.data()));
  @@ -322,7 +322,7 @@ namespace vks
  // Index buffer
  VK_CHECK_RESULT(device->createBuffer(
  VK_BUFFER_USAGE_TRANSFER_SRC_BIT,
  - VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT,
  + VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT,
  &indexStaging,
  iBufferSize,
  indexBuffer.data()));
  