iOS 获取当前毫秒数

可用于查询代码运行时间

获取毫秒时间戳
https://blog.csdn.net/ifziv/article/details/21703591

UInt64 recordTime = [[NSDate date] timeIntervalSince1970]*1000;

NSDateFormatter * formatter = [[NSDateFormatter alloc ] init];  
[formatter setDateFormat:@"YYYY-MM-dd hh:mm:ss:SSS"];    
NSString *date =  [formatter stringFromDate:[NSDate date]];  
NSString *timeLocal = [[NSString alloc] initWithFormat:@"%@", date]; 
NSLog(@"%@", timeLocal);