/// <summary>
/// 构造函数, 创建一个线程安全，顺序返回0..n-1的循环计数器
/// </summary>
/// <param name="n">上限</param>
public LoopCounter(int n)
{
if (n > 10000)
{
throw new NotSupportedException("Only support n <= 10000");
}
if (n == 0)
{
throw new NotSupportedException("Bad parameter n == 0");
}
//
//
_n = n;
_mask = NumberUtils.NextPower2(n * 40000) - 1;
_i = 0;
}