Return the frame header (as an array of bytes).

def header(self):
        """Return the frame header (as an array of bytes)."""
        total_length = self.total_length()
        res = [0x06, 0x10, 0, 0, 0, 0]
        res[2] = (self.service_type_id >> 8) & 0xff
        res[3] = (self.service_type_id >> 0) & 0xff
        res[4] = (total_length >> 8) & 0xff
        res[5] = (total_length >> 0) & 0xff
        return res