Function vkGetRefreshCycleDurationGOOGLE 

pub unsafe extern "system" fn vkGetRefreshCycleDurationGOOGLE(
    device: VkDevice,
    swapchain: VkSwapchainKHR,
    pDisplayTimingProperties: *mut VkRefreshCycleDurationGOOGLE,
) -> VkResult

Available if built with prototypes.