Use main thread for callback and add registerNetworkCallbackCompat

mobile/src/main/java/be/mygod/vpnhotspot/util/Services.kt

@@ -2,8 +2,12 @@ package be.mygod.vpnhotspot.util
 
 import android.content.Context
 import android.net.ConnectivityManager
+import android.net.NetworkRequest
 import android.net.wifi.WifiManager
 import android.net.wifi.p2p.WifiP2pManager
+import android.os.Build
+import android.os.Handler
+import android.os.Looper
 import androidx.core.content.getSystemService
 import timber.log.Timber
 
@@ -14,6 +18,7 @@ object Services {
         contextInit = context
     }
 
+    val mainHandler by lazy { Handler(Looper.getMainLooper()) }
     val connectivity by lazy { context.getSystemService<ConnectivityManager>()!! }
     val p2p by lazy {
         try {
@@ -24,4 +29,8 @@ object Services {
         }
     }
     val wifi by lazy { context.getSystemService<WifiManager>()!! }
+
+    fun registerNetworkCallbackCompat(request: NetworkRequest, networkCallback: ConnectivityManager.NetworkCallback) =
+        if (Build.VERSION.SDK_INT >= 26) connectivity.registerNetworkCallback(request, networkCallback, mainHandler)
+        else connectivity.registerNetworkCallback(request, networkCallback)
 }