save before flutter upgrade

lib/functions/phone_format.dart

@@ -0,0 +1,4 @@
+String formatPhone(String phone) {
+  if (phone.length != 10) return phone;
+  return '(${phone.substring(0, 3)}) ${phone.substring(3, 6)} ${phone.substring(6, 8)} ${phone.substring(8, 10)}';
+}