Add example of OwningRows using self_cell

examples/owning_rows_self_cell.rs

@@ -0,0 +1,27 @@
+extern crate rusqlite;
+
+use rusqlite::{CachedStatement, Connection, Result, Rows};
+use self_cell::{self_cell, MutBorrow};
+
+type RowsRef<'a> = Rows<'a>;
+
+self_cell!(
+    struct OwningRows<'conn> {
+        owner: MutBorrow<CachedStatement<'conn>>,
+        #[covariant]
+        dependent: RowsRef,
+    }
+);
+
+fn main() -> Result<()> {
+    let conn = Connection::open_in_memory()?;
+    let stmt = conn.prepare_cached("SELECT 1")?;
+    let mut or = OwningRows::try_new(MutBorrow::new(stmt), |s| s.borrow_mut().query([]))?;
+    or.with_dependent_mut(|_stmt, rows| -> Result<()> {
+        while let Some(row) = rows.next()? {
+            assert_eq!(Ok(1), row.get(0));
+        }
+        Ok(())
+    })?;
+    Ok(())
+}