c# ta long seek(long pozisyon,long uzunluk)

using System; 
  using System.IO; 
   
  class FStream 
  { 
      static void Main() 
      { 
          const string fileName = "Test#@@#.dat"; 
   
          // Create random data to write to the file. 
          byte[] dataArray = new byte[100000]; 
          new Random().NextBytes(dataArray); 
   
          using(FileStream   
              fileStream = new FileStream(fileName, FileMode.Create)) 
          { 
              // Write the data to the file, byte by byte. 
              for(int i = 0; i < dataArray.Length; i++) 
              { 
                  fileStream.WriteByte(dataArray[i]); 
              } 
   
              // Set the stream position to the beginning of the file. 
              fileStream.Seek(0, SeekOrigin.Begin); 
   
              // Read and verify the data. 
              for(int i = 0; i < fileStream.Length; i++) 
              { 
                  if(dataArray[i] != fileStream.ReadByte()) 
                  { 
                      Console.WriteLine("Error writing data."); 
                      return; 
                  } 
              } 
              Console.WriteLine("The data was written to {0} " + 
                  "and verified.", fileStream.Name); 
          } 
      } 
  }