How to convert WWW type to FileStream?

Now I directly convert the WWW varible to byte. But it has some problem. Firstly I want to convert the WWW to FileStream and then convert to byte. How to convert WWW type to FileStream? Thank you very much.

My code below:

int i, j, n, m = 0, nFileSize; byte[] abybuf = null; char[] abybufChar = null; FileStream stFile = null; string path;

if (flagPlatform == androidPlatform) {

             WWW www = new WWW("jar:file://" + Application.dataPath + "!/assets/help_text.dat");
             abybuf = new byte[www.bytes.Length];
             abybuf = www.bytes;


             short[] nHelpPos = { 9, 6, 9, 9, 7, 4, 7, 8,
                                 6, 6, 9, 6, 7, 7, 9, 8, 8, 7,
                                 4, 9, 4, 9, 9, 9, 9, 6, 7 };


             n = 0;
             for (i = 0; i < m_stHelpList.Length; i++)
             {
                 m_stHelpList = new string[nHelpPos];
                 for (j = 0; j < nHelpPos; j++)
                 {
                     nFileSize = (abybuf[n+=1] & 0xFF);
                     m_stHelpList[j] = System.Text.Encoding.GetEncoding("utf-8").GetString(abybuf, n, nFileSize);
                     n += nFileSize;
                 }
             }
     }
     else
     {


         {
             path = Application.dataPath + "/StreamingAssets/help_text.dat";
         }
         stFile = new FileStream(path, FileMode.Open, FileAccess.Read);


         abybuf = new byte[(stFile.ReadByte() & 0xFF) | ((stFile.ReadByte() & 0xFF) << 8)];
         stFile.Read(abybuf, 0, abybuf.Length);


         short[] nHelpPos = { 9, 6, 9, 9, 7, 4, 7, 8,
                                 6, 6, 9, 6, 7, 7, 9, 8, 8, 7,
                                 4, 9, 4, 9, 9, 9, 9, 6, 7 };


         n = 0;
         for (i = 0; i < m_stHelpList.Length; i++)
         {
             m_stHelpList = new string[nHelpPos];
             for (j = 0; j < nHelpPos; j++)
             {
                 nFileSize = (abybuf[n++] & 0xFF);
                 m_stHelpList[j] = System.Text.Encoding.GetEncoding("utf-8").GetString(abybuf, n, nFileSize);
                 n += nFileSize;
             }
         }


     }