total size of entire memory block if successful.
GC.extend
size_t extend(void * p, size_t minsize, size_t maxsize, const TypeInfo ti) nothrow;Attempt to in-place enlarge the memory block pointed to by p by at least minsize bytes, up to a maximum of maxsize additional bytes. This does not attempt to move the memory block (like realloc() does).
Returns
0 if could not extend p,