added askpermission and partial startAdvertising methods

lib/nearby_connections.dart

@@ -2,6 +2,9 @@ import 'dart:async';
 
 import 'package:flutter/services.dart';
 
+enum STRATEGY { P2P_CLUSTER, P2P_STAR, P2P_POINT_TO_POINT }
+enum Status { NONE, SUCCESS, FAILURE, IN_PROGRESS, CANCELED }
+
 class Nearby {
   //for maintaining only 1 instance of this class
   static final Nearby _instance = Nearby._();
@@ -14,4 +17,37 @@ class Nearby {
   Future<bool> checkPermissions() async => await _channel.invokeMethod(
         'checkPermissions',
       );
+
+  Future<void> askPermission() async {
+    await _channel.invokeMethod(
+      'askPermissions',
+    );
+  }
+
+  Future<bool> startAdvertising(String userNickName, STRATEGY strategy) async {
+    assert(userNickName != null && strategy != null);
+
+    return await _channel.invokeMethod('startAdvertising', <String, dynamic>{
+      'userNickName': userNickName,
+      'strategy': strategy.index
+    });
+  }
+
+  Future<void> stopAdvertising() async {
+    await _channel.invokeMethod('stopAdvertising');
+  }
+}
+
+abstract class ConnectionLifecycleCallback {
+  void onConnectionInitiated(String s, ConnectionInfo connectionInfo);
+  void onConnectionResult(String s, Status status);
+  void onDisconnected(String s) {}
+}
+
+class ConnectionInfo {
+  String endPointName, authenticationToken;
+  bool isIncomingConnection;
+
+  ConnectionInfo(
+      this.endPointName, this.authenticationToken, this.isIncomingConnection);
 }