线程的优先级

    NSThread *t1 = [[NSThread alloc] initWithTarget:self selector:@selector(createThreadOne) object:nil];
    t1.name = @"线程A";
    //修改优先级
    t1.threadPriority = 0;
    [t1 start];
    
    NSThread *t2 = [[NSThread alloc] initWithTarget:self selector:@selector(createThreadTwo) object:nil];
    t2.name = @"线程B";
    t2.threadPriority = 1;
    [t2 start];