Function set_isr_yielder 

#[unsafe(link_section = ".iram1.interrupt_set_isr_yielder")]
pub unsafe fn set_isr_yielder(
    yielder: Option<(unsafe fn(*mut ()), *mut ())>,
) -> Option<(unsafe fn(*mut ()), *mut ())>

Safety

This function should only be called from within an ISR handler, so as to set a custom ISR yield function (e.g. when using the ESP-IDF timer service).

Thus, if some function further down the ISR call chain invokes do_yield, the custom yield function set here will be called.

Users should not forget to call again set_isr_yielder at the end of the ISR handler so as to reastore the yield function which was valid before the ISR handler was invoked.