Function vkGetSwapchainCounterEXT 

pub unsafe extern "system" fn vkGetSwapchainCounterEXT(
    device: VkDevice,
    swapchain: VkSwapchainKHR,
    counter: VkSurfaceCounterFlagBitsEXT,
    pCounterValue: *mut u64,
) -> VkResult

Available if built with prototypes.