1arc {
2  anchor_angle: {
3    value: 0
4  }
5  anchor_type: {
6    value: ARC_ANCHOR_START
7  }
8  contents {
9    line {
10      length {
11        value: 100
12      }
13      thickness {
14        value: 10
15      }
16      color {
17        argb: 0xFFFF0000
18      }
19    }
20  }
21}
22