Type Alias PresentHook 

pub type PresentHook = Box<dyn FnMut(&Frame<'_>)>;

What runs on each frame a HeadlessPlatform is presented, in its present: the work a device’s backend does there, such as a one-bit display’s conversion, so a frame measured headless counts it (HeadlessPlatform::set_present_hook).

Aliased Type

pub struct PresentHook(/* private fields */);