Compares the two Bytes values.
This function can be used to sort GBytes instances in lexicographical order.
If this and
bytes2 have different length but the shorter one is a prefix of the longer one then
the shorter one is considered to be less than the longer one. Otherwise the first byte where both differ is used for comparison. If
this has a smaller value at that position it is considered less, otherwise greater than
a pointer to a Bytes
a pointer to a Bytes to compare with this
a negative value if this is less than