golang goroutine 同步访问变量的问题

E:\gocode>hello2
[-----Send A+1],[13],id[0]
id[0]
sleeping [Send B+1],[8],id[1]
[-----Send A+2],[13],id[0]
id[0]
[-----Send A+3],[13],id[0]
id[0]
[-----Send A+4],[13],id[0]
id[0]
[-----Send A+5],[13],id[0]
id[0]
[-----Send A+6],[13],id[0]
id[0]
[-----Send A+7],[13],id[0]
id[0]
[-----Send A+7],[13],id[1]
id[1]
sleeping [Send B+2],[8],id[1]
[-----Send A+8],[13],id[0]
id[0]
[-----Send A+9],[13],id[0]
id[0]
[-----Send A+9],[13],id[1]
id[1]
sleeping [Send B+3],[8],id[1]
[Send B+3],[8],id[1]
id[1]
sleeping [Send B+4],[8],id[1]
[Send B+4],[8],id[1]
id[1]
sleeping [Send B+5],[8],id[1]
[Send B+5],[8],id[1]
id[1]
sleeping [Send B+6],[8],id[1]
[Send B+6],[8],id[1]
id[1]
sleeping [Send B+7],[8],id[1]
[Send B+7],[8],id[1]
id[1]
sleeping [Send B+8],[8],id[1]
[Send B+8],[8],id[1]
id[1]
sleeping [Send B+9],[8],id[1]
[Send B+9],[8],id[1]
id[1]