We should sync.

main.go

@@ -33,6 +33,7 @@ type transientMsg struct {
 type WriteSeekCloser interface {
 	io.WriteSeeker
 	io.Closer
+	Sync() error
 }
 
 type model struct {
@@ -173,7 +174,8 @@ func (m model) writeFile() error {
 	if err != nil {
 		return fmt.Errorf("write: %w", err)
 	}
-	return nil
+
+	return m.fh.Sync()
 }
 
 func (m model) View() tea.View {