Function to_shmem::to_shmem_slice_ptr

pub(crate) unsafe fn to_shmem_slice_ptr<'a, T, I>(
    src: I,
    dest: *mut T,
    builder: &mut SharedMemoryBuilder,
) -> Result<*mut [T], String>
where
    T: 'a + ToShmem,
    I: ExactSizeIterator<Item = &'a T>,

Converts all the items in src into shared memory form, writes them into the specified buffer, and returns a pointer to the slice.