import struct


def timestamp_to_bytes(t):
    """Convert timestamp to 96 bit representation

    Bits 0 - 63 are big endian two's complement encoded :attr:`Timestamp.s` and
    bits 64 - 95 are big endian two's complement encoded :attr:`Timestamp.us`.

    Args:
        t (Timestamp): timestamp

    Returns:
        bytes

    """
    return struct.pack(">QI", t.s + (1 << 63), t.us)