using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Threading;
class Program
{
static void Main(string[] args)
{
FileStream fs = new FileStream("logfile.txt", FileMode.Append,FileAccess.Write, FileShare.None, 4096, true);
string msg = "this is a test";
byte[] buffer = Encoding.ASCII.GetBytes(msg);
fs.BeginWrite(buffer, 0, buffer.Length,new AsyncCallback(WriteDone), fs);
}
private static void WriteDone(IAsyncResult ar)
{
Stream s = (Stream)ar.AsyncState;
s.EndWrite(ar);
s.Close();
}
}