images.captureScreen(); 随调用次数增多会变的极为缓慢，执行速度很不稳定

[nsy9601]

let start = new Date();
for (let index = 0; index < 100; index++) {
	let start = new Date();
	images.captureScreen();
	console.info('耗时' + (new Date() - start) + 'ms', index);
}

上面为代码，下面为调试输出的结果：

15:55:13.550/I: 耗时15ms 0
15:55:13.568/I: 耗时18ms 1
15:55:13.586/I: 耗时17ms 2
15:55:13.603/I: 耗时16ms 3
15:55:13.619/I: 耗时16ms 4
15:55:13.636/I: 耗时17ms 5
15:55:13.653/I: 耗时17ms 6
15:55:13.669/I: 耗时16ms 7
15:55:13.709/I: 耗时39ms 8
15:55:13.970/I: 耗时261ms 9
15:55:14.427/I: 耗时455ms 10
15:55:15.327/I: 耗时899ms 11
15:55:18.451/I: 耗时3124ms 12
15:55:26.482/I: 耗时8030ms 13
15:55:30.502/I: 耗时4019ms 14
15:55:34.538/I: 耗时4036ms 15
15:55:38.559/I: 耗时4021ms 16
15:55:42.587/I: 耗时4027ms 17
15:55:46.607/I: 耗时4019ms 18
15:55:50.627/I: 耗时4019ms 19
15:55:54.649/I: 耗时4021ms 20
15:55:54.796/I: 耗时146ms 21
15:55:57.827/I: 耗时3030ms 22
15:55:58.646/I: 耗时818ms 23
15:56:00.062/I: 耗时1415ms 24
15:56:02.671/I: 耗时2608ms 25
15:56:06.933/I: 耗时4262ms 26
15:56:10.004/I: 耗时3070ms 27
15:56:14.705/I: 耗时4699ms 28
15:56:16.417/I: 耗时1712ms 29
15:56:18.725/I: 耗时2307ms 30
15:56:22.753/I: 耗时4028ms 31
15:56:26.771/I: 耗时4017ms 32
15:56:30.790/I: 耗时4019ms 33
15:56:31.642/I: 耗时850ms 34
15:56:42.843/I: 耗时11201ms 35
15:56:46.848/I: 耗时4004ms 36
15:56:50.869/I: 耗时4021ms 37
15:56:54.891/I: 耗时4022ms 38
15:56:58.603/I: 耗时3711ms 39
15:57:00.083/I: 耗时1480ms 40
15:57:01.616/I: 耗时1533ms 41
15:57:06.940/I: 耗时5323ms 42
15:57:10.962/I: 耗时4022ms 43
15:57:11.797/I: 耗时834ms 44
15:57:11.810/I: 耗时13ms 45
15:57:11.821/I: 耗时11ms 46
15:57:11.833/I: 耗时11ms 47
15:57:11.844/I: 耗时11ms 48
15:57:11.855/I: 耗时11ms 49
15:57:11.866/I: 耗时11ms 50
15:57:11.878/I: 耗时11ms 51
15:57:11.889/I: 耗时10ms 52
15:57:11.900/I: 耗时11ms 53
15:57:11.912/I: 耗时12ms 54
15:57:11.926/I: 耗时14ms 55
15:57:11.940/I: 耗时14ms 56
15:57:11.954/I: 耗时14ms 57
15:57:11.968/I: 耗时13ms 58
15:57:11.981/I: 耗时13ms 59
15:57:11.995/I: 耗时13ms 60
15:57:12.010/I: 耗时14ms 61
15:57:12.025/I: 耗时14ms 62
15:57:12.040/I: 耗时14ms 63
15:57:12.055/I: 耗时15ms 64
15:57:12.070/I: 耗时15ms 65
15:57:12.085/I: 耗时15ms 66
15:57:12.101/I: 耗时16ms 67
15:57:12.116/I: 耗时15ms 68
15:57:12.131/I: 耗时15ms 69
15:57:12.146/I: 耗时14ms 70
15:57:12.160/I: 耗时14ms 71
15:57:12.174/I: 耗时13ms 72
15:57:14.973/I: 耗时2798ms 73
15:57:14.989/I: 耗时16ms 74
15:57:17.441/I: 耗时2451ms 75
15:57:17.458/I: 耗时16ms 76
15:57:17.478/I: 耗时20ms 77
15:57:17.501/I: 耗时23ms 78
15:57:17.518/I: 耗时17ms 79
15:57:17.535/I: 耗时17ms 80
15:57:17.553/I: 耗时18ms 81
15:57:17.573/I: 耗时20ms 82
15:57:17.593/I: 耗时20ms 83
15:57:17.613/I: 耗时20ms 84
15:57:17.633/I: 耗时20ms 85
15:57:17.654/I: 耗时20ms 86
15:57:19.002/I: 耗时1347ms 87
15:57:23.017/I: 耗时4015ms 88
15:57:31.023/I: 耗时8005ms 89
15:57:35.040/I: 耗时4016ms 90
15:57:36.191/I: 耗时1149ms 91
15:57:36.204/I: 耗时13ms 92
15:57:36.221/I: 耗时16ms 93
15:57:36.241/I: 耗时20ms 94
15:57:36.264/I: 耗时23ms 95
15:57:36.283/I: 耗时19ms 96
15:57:36.302/I: 耗时18ms 97
15:57:36.323/I: 耗时19ms 98
15:57:36.342/I: 耗时19ms 99