Add example of OwningStatement using ouroboros

examples/owning_statement.rs

@@ -0,0 +1,27 @@
+extern crate rusqlite;
+use ouroboros::self_referencing;
+use rusqlite::{CachedStatement, Connection, Result, Rows};
+
+#[self_referencing]
+struct OwningStatement {
+    conn: Connection,
+    #[borrows(conn)]
+    #[covariant]
+    stmt: CachedStatement<'this>,
+}
+
+fn main() -> Result<()> {
+    let conn = Connection::open_in_memory()?;
+
+    let mut os = OwningStatementTryBuilder {
+        conn,
+        stmt_builder: |c| c.prepare_cached("SELECT 1"),
+    }
+    .try_build()?;
+
+    let mut rows = os.with_stmt_mut(|stmt| -> Result<Rows<'_>> { stmt.query([]) })?;
+    while let Some(row) = rows.next()? {
+        assert_eq!(Ok(1), row.get(0));
+    }
+    Ok(())
+}