使用snapshot()的时候有概率会socket断开

**详细描述问题bug：**
使用snapshot()命令的时候，会报错Traceback (most recent call last)
提示我OSError: socket connection broken

**复现步骤：**
ResultTime = datetime.datetime.now().strftime('%m%d%H%M%S')
FailShot = PvpLadderNowtimePath + "\\" + ResultTime + "_fail_FightResult.jpg"
SucessShot = PvpLadderNowtimePath + "\\" + ResultTime + "_Succes_FightResult.jpg"
timeResult = 0
while timeResult < 1000 and not poco(text="继续"):
FightingTime = datetime.datetime.now().strftime('%m%d%H%M%S')
FightingShot = PvpLadderNowtimePath + "\\" + FightingTime + "_fighting.jpg"
time.sleep(5)
snapshot(FightingShot)
time.sleep(5)
timeResult += 10
sys.stdout.flush()
if timeResult > 600:
print ("报错++++++++++++++++++++程序error")
sys.stdout.flush()
time.sleep(2)
snapshot(FailShot)
time.sleep(2)
restart_program()
snapshot(SucessShot)
time.sleep(5)
poco(text="继续").click()

**python 版本:** `python3.6.5

**操作系统:** `Windows10 64bit`

**手机设备信息:**
- 手机型号: 夜神模拟器6.3.0.2

**其他相关信息补充**
(例如在linux ubuntu16.04上运行异常，在windows上正常等信息。)
- AirtestIDE版本号：1.1.0
adb版本： 1.0.40

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