Type Alias PFN_vkDebugUtilsMessengerCallbackEXT 

pub type PFN_vkDebugUtilsMessengerCallbackEXT = extern "system" fn(DebugUtilsMessageSeverityFlagBitsEXT, DebugUtilsMessageTypeFlagsEXT, *const DebugUtilsMessengerCallbackDataEXT, *mut c_void) -> Bool32;