Function request_idle_callback 

pub fn request_idle_callback(cb: impl Fn() + 'static)

Queues the given function during an idle period using Window.requestIdleCallback.

Note about Context

The callback is called outside of the reactive ownership tree. This means that it does not have access to context via use_context. If you want to use context inside the callback, you should either call use_context in the body of the component, and move the value into the callback, or access the current owner inside the component body using Owner::current and reestablish it in the callback with Owner::with.