Method insert_layout

Insert a new object to `Layout` mapping. `insert_layout` is passed a pointer to a newly-allocated object and a `Layout` describing that object, and it stores this mapping. `insert_layout` is called immediately after allocation in all of the C allocation functions. The default implementation of `insert_layout` is a no-op, as some allocators may already keep track of the information necessary to i

(&self, _ptr: *mut u8, _layout: Layout)