126     pub async fn write(&self, packet: &[u8]) -> Result<usize> {  in write()
127         if packet.len() >= 0x10000 {  in write()
138             || (b.limit_size > 0 && b.size() + 2 + packet.len() > b.limit_size)  in write()
144         while !b.available(packet.len()) {  in write()
150         b.data[tail] = (packet.len() >> 8) as u8;  in write()
157         b.data[tail] = packet.len() as u8;  in write()
164         let end = std::cmp::min(b.data.len(), b.tail + packet.len());  in write()
167         b.data[tail..end].copy_from_slice(&packet[..n]);  in write()
171             let m = packet.len() - n;  in write()
172             b.data[..m].copy_from_slice(&packet[n..]);  in write()
183         Ok(packet.len())  in write()
190     pub async fn read(&self, packet: &mut [u8], duration: Option<Duration>) -> Result<usize> {  in read()
212                     if copied > packet.len() {  in read()
213                         copied = packet.len();  in read()
218                         packet[..copied].copy_from_slice(&b.data[b.head..b.head + copied]);  in read()
221                         packet[..k].copy_from_slice(&b.data[b.head..]);  in read()
222                         packet[k..copied].copy_from_slice(&b.data[..copied - k]);  in read()