Struct GridPayload 

#[repr(C)]
pub struct GridPayload {
    pub element_descriptor: *const TypeDescriptor,
    pub items: Vec<GcRef>,
    pub width: usize,
}

The Grid[T] payload: a row-major sequence of GcRefs plus the fixed column count (width). items.len() == width * height. Mirrors VecPayload but carries rectangular shape so indexing and neighbourhood walks are cheap.

Fields

element_descriptor: *const TypeDescriptor

The descriptor for every cell in items, or null for “not told yet” — VecPayload::element_descriptor’s contract exactly. Read it through [ElementSeq::element].

items: Vec<GcRef>

Row-major cells: items[row * width + col].

width: usize

The number of columns (all rows share this width).