private void FillSize(SprotoStream writer, int pos, UInt32 size)
{
//Console.WriteLine("*FillSize: pos={0},size={1}",pos,size);
int curpos = writer.Position;
writer.Seek(pos, SprotoStream.SEEK_BEGIN);
this.WriteUInt32(writer, size);
writer.Seek(curpos, SprotoStream.SEEK_BEGIN);
}