MangaScreenModel: Start downloads in IO dispatcher (#10241)

app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaScreenModel.kt

@@ -636,18 +636,18 @@ class MangaScreenModel(
     ) {
         val successState = successState ?: return
 
-        if (startNow) {
-            val chapterId = chapters.singleOrNull()?.id ?: return
-            downloadManager.startDownloadNow(chapterId)
-        } else {
-            downloadChapters(chapters)
-        }
-
-        if (!isFavorited && !successState.hasPromptedToAddBefore) {
-            updateSuccessState { state ->
-                state.copy(hasPromptedToAddBefore = true)
+        screenModelScope.launchNonCancellable {
+            if (startNow) {
+                val chapterId = chapters.singleOrNull()?.id ?: return@launchNonCancellable
+                downloadManager.startDownloadNow(chapterId)
+            } else {
+                downloadChapters(chapters)
             }
-            screenModelScope.launch {
+
+            if (!isFavorited && !successState.hasPromptedToAddBefore) {
+                updateSuccessState { state ->
+                    state.copy(hasPromptedToAddBefore = true)
+                }
                 val result = snackbarHostState.showSnackbar(
                     message = context.stringResource(MR.strings.snack_add_to_library),
                     actionLabel = context.stringResource(MR.strings.action_add),