19     head: usize,  field
34         let mut available = self.head as isize - self.tail as isize;  in available()
70         if self.head <= self.tail {  in grow()
72             n = self.tail - self.head;  in grow()
73             newdata[..n].copy_from_slice(&self.data[self.head..self.tail]);  in grow()
76             n = self.data.len() - self.head;  in grow()
77             newdata[..n].copy_from_slice(&self.data[self.head..]);  in grow()
81         self.head = 0;  in grow()
89         let mut size = self.tail as isize - self.head as isize;  in size()
108                 head: 0,  in new()
196                 if b.head != b.tail {  in read()
198                     let n1 = b.data[b.head];  in read()
199                     b.head += 1;  in read()
200                     if b.head >= b.data.len() {  in read()
201                         b.head = 0;  in read()
203                     let n2 = b.data[b.head];  in read()
204                     b.head += 1;  in read()
205                     if b.head >= b.data.len() {  in read()
206                         b.head = 0;  in read()
217                     if b.head + copied < b.data.len() {  in read()
218                         packet[..copied].copy_from_slice(&b.data[b.head..b.head + copied]);  in read()
220                         let k = b.data.len() - b.head;  in read()
221                         packet[..k].copy_from_slice(&b.data[b.head..]);  in read()
226                     b.head += count;  in read()
227                     if b.head >= b.data.len() {  in read()
228                         b.head -= b.data.len();  in read()
231                     if b.head == b.tail {  in read()
234                         b.head = 0;  in read()