add invoice pdf

lib/data/services/invoice_imp.dart

@@ -0,0 +1,34 @@
+import 'package:fcs/data/provider/invoice_data_provider.dart';
+import 'package:fcs/data/provider/shipment_data_provider.dart';
+import 'package:fcs/data/services/shipment_service.dart';
+import 'package:fcs/domain/entities/connectivity.dart';
+import 'package:fcs/domain/entities/invoice.dart';
+import 'package:fcs/domain/entities/shipment.dart';
+import 'package:flutter/material.dart';
+
+import 'invoice_service.dart';
+
+class InvoiceServiceImp implements InvoiceService {
+  InvoiceServiceImp({
+    @required this.invoiceDataProvider,
+    @required this.connectivity,
+  });
+
+  final Connectivity connectivity;
+  final InvoiceDataProvider invoiceDataProvider;
+
+  @override
+  Future<void> cancelInvoice(Invoice invoice) {
+    return invoiceDataProvider.cancelInvoice(invoice);
+  }
+
+  @override
+  Future<void> createInvoice(Invoice invoice) {
+    return invoiceDataProvider.createInvoice(invoice);
+  }
+
+  @override
+  Future<void> updateInvoice(Invoice invoice) {
+    return invoiceDataProvider.updateInvoice(invoice);
+  }
+}