def head_sequence(self):
return self._encode_invoke(ringbuffer_head_sequence_codec)<EOL>
Returns the sequence of the head. The head is the side of the Ringbuffer where the oldest items in the
Ringbuffer are found. If the Ringbuffer is empty, the head will be one more than the tail. The initial value of
the head is 0 (1 more than tail).

:return: (long), the sequence of the head.