message: feat(c-api) Transmute boxed vecs to `Vec<Option<Box<T>>>` when deleting.
  It's a safer way to handle partially uninitialized boxed vector, since
  it protects against based deletion for every item.
diff: @@ -345,13 +345,7 @@ See the [`wasm_" $name "_vec_t`] type to get an example."]
  if let Some(vec) = ptr {
  if !vec.data.is_null() {
  let data: Vec<*mut [<wasm_ $name _t>]> = Vec::from_raw_parts(vec.data, vec.size, vec.size);
  -
  - // If the vector has been initialized (we check
  - // only the first item), we can transmute items to
  - // `Box`es.
  - if vec.size > 0 && !data[0].is_null() {
  - let _data: Vec<Box<[<wasm_ $name _t>]>> = ::std::mem::transmute(data);
  - }
  + let _data: Vec<Option<Box<[<wasm_ $name _t>]>>> = ::std::mem::transmute(data);
  vec.data = ::std::ptr::null_mut();
  vec.size = 0;
  