public void Dump()
{
Console.WriteLine("Head={0} Tail={1} Cursor={2} count={3}", head, tail, cursor, count);
for (int i = 0; i < history.Length; i++)
{
Console.WriteLine(" {0} {1}: {2}", i == cursor ? "==>" : " ", i, history[i]);
}
//log.Flush ();
}