Function vkBuildMicromapsEXT 

pub unsafe extern "system" fn vkBuildMicromapsEXT(
    device: VkDevice,
    deferredOperation: VkDeferredOperationKHR,
    infoCount: u32,
    pInfos: *const VkMicromapBuildInfoEXT,
) -> VkResult

Available if built with prototypes.