Function rcl_sys::rcl::timer::rcl_timer_get_time_until_next_call

pub unsafe extern "C" fn rcl_timer_get_time_until_next_call(
    timer: *const rcl_timer_t, 
    time_until_next_call: *mut i64
) -> rcl_ret_t

Calculate and retrieve the time until the next call in nanoseconds.