Like sort, but uses a SequenceIterCompareFunc instead of a GCompareDataFunc as the compare function
cmp_func is called with two iterators pointing into this. It should return 0 if the
iterators are equal, a negative value if the first iterator comes before the second, and a positive value if the second iterator comes
before the first.
| this |
a Sequence |
| cmp_data |
user data passed to |
| cmp_func |
the function used to compare iterators in the sequence |