fn drop(&mut self) {
        if let Some(ref mut guard) = self.guard {
            guard.queue.pop_front();
            guard.notify_ready();
        }
    }
/// When the `WaitQueueHandle` goes out of scope, we pop the current thread from the front of
/// the wait queue and notify the wait queue that it can wake up the next thread.
When the `WaitQueueHandle` goes out of scope, we pop the current thread from the front of
the wait queue and notify the wait queue that it can wake up the next thread.
When the ` WaitQueueHandle ` goes out of scope we pop the current thread from the front of the wait queue and notify the wait queue that it can wake up the next thread .
fn drop(&mut self) {
        if let Some(ref mut guard) = self.guard {
            guard.queue.pop_front();
            guard.notify_ready();
        }
    }
fn drop ( & mut self ) { if let Some ( ref mut guard ) = self . guard { guard . queue . pop_front ( ) ; guard . notify_ready ( ) ; } }
When the `WaitQueueHandle` goes out of scope, we pop the current thread from the front of
the wait queue and notify the wait queue that it can wake up the next thread.
When the ` WaitQueueHandle ` goes out of scope we pop the current thread from the front of the wait queue and notify the wait queue that it can wake up the next thread .
&mut self
&mut self