Allocates a block of memory from the slice allocator.
The block address handed out can be expected to be aligned
to at least
1 * sizeof (void*), though in general slices
2 * sizeof (void*) bytes aligned; if a
fallback implementation is used instead, the alignment may
be reduced in a libc dependent fashion.
Note that the underlying slice allocation mechanism can
be changed with the [
Available since: 2.10