Add ability to skip number of records

bin/owntracks_import.dart

@@ -13,6 +13,9 @@ ArgParser buildParser() {
     ..addOption('destination',
         abbr: 'd', help: 'OwnTracks Recorder server address')
     ..addOption('user', abbr: 'u', help: 'User for OwnTrack record')
+    ..addOption('continue',
+        abbr: 'c',
+        help: 'The number of record to continue import from (Starting from 1)')
     ..addFlag(
       'help',
       abbr: 'h',
@@ -81,9 +84,34 @@ void main(List<String> arguments) async {
 
     final List<dynamic> failedList = [];
 
+    final rawContinueFrom = results.option('continue');
+
+    final continueFrom =
+        rawContinueFrom == null ? 1 : int.parse(rawContinueFrom);
+
     int n = 1;
 
+    if (continueFrom > recordsList.length) {
+      throw FormatException('There are only ${recordsList.length} in the list');
+    }
+
     for (final record in recordsList) {
+      if (n < continueFrom) {
+        if (verbose) {
+          print(' ');
+          print('Record $n of ${recordsList.length} SKIPPED');
+        }
+
+        n++;
+
+        continue;
+      }
+
+      if (verbose) {
+        print(' ');
+        print('Record $n of ${recordsList.length}');
+      }
+
       final Map<String, dynamic> payload = {'_type': 'location', 't': 'u'};
 
       final recordProps = record['properties'];
@@ -121,8 +149,6 @@ void main(List<String> arguments) async {
       payload['conn'] = recordProps['connection'];
 
       if (verbose) {
-        print(' ');
-        print('Record $n of ${recordsList.length}');
         print(payload);
       }
 
@@ -137,7 +163,6 @@ void main(List<String> arguments) async {
       final url = '${results.option('destination')}/pub?u=$user&d=$device';
 
       if (verbose) {
-        print(' ');
         print('...Sending to: $url');
       }