138                 buf_slice.copy_from_slice(&temp[range.begin..range.end]);  in read_at()
173                 temp[range.begin..range.end].copy_from_slice(&buf_slice);  in write_at()
190     pub begin: usize, // 迭代器的起始位置 -> 块设备的地址 （单位是字节）  field
202     pub begin: usize, // 起始位置在块内的偏移量， 如果BlockIter启用Multiblock，则是多个块的偏移量  field
211             begin: start_addr,  in new()
219             begin: start_addr,  in new_multiblock()
230         let lba_id = self.begin / blk_size;  in next_block()
231         let begin = self.begin % blk_size;  in next_block()  localVariable
238         self.begin += end - begin;  in next_block()
243             begin: begin,  in next_block()
253         let lba_start = self.begin / blk_size;  in next_multiblock()
257         if __bytes_to_lba(self.begin, blk_size)  in next_multiblock()
258             != __bytes_to_lba(self.begin + blk_size - 1, blk_size)  in next_multiblock()
264         let begin = self.begin % blk_size; // 因为是多个整块，这里必然是0  in next_multiblock()  localVariable
265         let end = __lba_to_bytes(lba_end, blk_size) - self.begin;  in next_multiblock()
267         self.begin += end - begin;  in next_multiblock()
272             begin: begin,  in next_multiblock()
284         if self.begin >= self.end {  in next()
299         return self.end == self.begin;  in is_empty()
302         return self.end - self.begin;  in len()
315         return (self.lba_start << self.blk_size_log2) + self.begin;  in origin_begin()