Use AtomicReference for SmartSnackbar

mobile/src/main/java/be/mygod/vpnhotspot/widget/SmartSnackbar.kt

@@ -12,15 +12,15 @@ import be.mygod.vpnhotspot.App.Companion.app
 import be.mygod.vpnhotspot.util.readableMessage
 import com.google.android.material.snackbar.Snackbar
 import com.topjohnwu.superuser.NoShellException
+import java.util.concurrent.atomic.AtomicReference
 
 sealed class SmartSnackbar {
     companion object {
-        @SuppressLint("StaticFieldLeak")
-        private var holder: View? = null
+        private val holder = AtomicReference<View?>()
 
         fun make(@StringRes text: Int): SmartSnackbar = make(app.getText(text))
         fun make(text: CharSequence = ""): SmartSnackbar {
-            val holder = holder
+            val holder = holder.get()
             return if (holder == null) @SuppressLint("ShowToast") {
                 if (Looper.myLooper() == null) Looper.prepare()
                 ToastWrapper(Toast.makeText(app, text, Toast.LENGTH_LONG))
@@ -37,11 +37,9 @@ sealed class SmartSnackbar {
             view.findViewTreeLifecycleOwner()!!.lifecycle.addObserver(this)
         }
 
-        override fun onResume(owner: LifecycleOwner) {
-            holder = view
-        }
+        override fun onResume(owner: LifecycleOwner) = holder.set(view)
         override fun onPause(owner: LifecycleOwner) {
-            if (holder === view) holder = null
+            holder.compareAndSet(view, null)
         }
     }