public Stream OpenStream(string fullPath, PortableFileMode mode, PortableFileAccess access)
 {
     FileMode _mode = mode == PortableFileMode.CreateNew ? FileMode.CreateNew
         : mode == PortableFileMode.Create ? FileMode.Create
         : mode == PortableFileMode.Open ? FileMode.Open
         : mode == PortableFileMode.OpenOrCreate ? FileMode.OpenOrCreate
         : mode == PortableFileMode.Truncate ? FileMode.Truncate
         : FileMode.Append;
     FileAccess _access = access == PortableFileAccess.Read ? FileAccess.Read
         : access == PortableFileAccess.Write ? FileAccess.Write
         : FileAccess.ReadWrite;
     var stream = File.Open (fullPath, _mode, _access);
     return stream;
 }
 public Stream OpenStream(string fullPath, PortableFileMode mode, PortableFileAccess access)
 {
     return new MemoryStream (new byte[0]);
 }