Extend the rust_debugfs_scoped sample to demonstrate how to export a large binary object through a ScopedDir. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Matthew Maurer <mmaurer@google.com> Signed-off-by: Danilo Krummrich <dakr@kernel.org>