Function put_sharing

crates/ixon/src/serialize.rs:502–507

(sharing: &[Arc<Expr>], buf: &mut Vec<u8>)

          },
          Expr::FLAG_APP => {
            if tag.size == 0 {
              return Err("get_expr: App with zero args".to_string());
            }
            // Parse func, then collect args and wrap
            work.push(GetExprFrame::CollectApps(tag.size));
            work.push(GetExprFrame::Parse); // func
          },
          Expr::FLAG_LAM => {
            if tag.size == 0 {