214         for n in 0..MAX_DEVICES {  in add_device()
215             if self.devices[n].is_none() {  in add_device()
216                 self.devices[n] = Some(builder(self.next_id));  in add_device()
219                 return Ok(n as Id);  in add_device()
225     fn disconnect(&mut self, n: usize) {  in disconnect()
226         let id = self.devices[n].as_ref().unwrap().id;  in disconnect()
227         self.devices[n] = None;  in disconnect()
230             assert!(n != other_n);  in disconnect()
249         for n in 0..MAX_DEVICES {  in send()
250             let Some(ref device) = self.devices[n] else { continue };  in send()
266         for n in 0..MAX_DEVICES {  in poll()
267             let dropped = match self.devices[n] {  in poll()
271                         warn!("dropping device {}: {}", n, err);  in poll()
279                 self.disconnect(n)  in poll()