android: make SavedPostUpdater more parallel

android/src/main/kotlin/dev/msfjarvis/claw/android/work/SavedPostUpdaterWorker.kt

@@ -9,7 +9,11 @@ import dagger.assisted.AssistedInject
 import dev.msfjarvis.claw.android.viewmodel.SavedPostsRepository
 import dev.msfjarvis.claw.api.LobstersApi
 import dev.msfjarvis.claw.common.posts.toDbModel
+import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.async
+import kotlinx.coroutines.awaitAll
 import kotlinx.coroutines.flow.first
 
 /**
@@ -18,6 +22,7 @@ import kotlinx.coroutines.flow.first
  * saved posts that were saved before comment counts were added to be able to show a comment count
  * and for new-enough posts that are still getting comments to have an accurate one.
  */
+@Suppress("DEPRECATION") // We're being nasty
 @OptIn(ExperimentalCoroutinesApi::class)
 @HiltWorker
 class SavedPostUpdaterWorker
@@ -29,12 +34,17 @@ constructor(
   @Assisted workerParams: WorkerParameters,
 ) : CoroutineWorker(appContext, workerParams) {
   override suspend fun doWork(): Result {
-    savedPostsRepository
-      .savedPosts
-      .first()
-      .mapNotNull { post -> runCatching { lobstersApi.getPostDetails(post.shortId) }.getOrNull() }
-      .map { postDetails -> postDetails.toDbModel() }
-      .map { post -> savedPostsRepository.savePost(post) }
+    val posts = savedPostsRepository.savedPosts.first()
+    posts
+      .map { post ->
+        CoroutineScope(coroutineContext + Job()).async {
+          val details = runCatching { lobstersApi.getPostDetails(post.shortId) }.getOrNull()
+          if (details != null) {
+            savedPostsRepository.savePost(details.toDbModel())
+          }
+        }
+      }
+      .awaitAll()
     return Result.success()
   }
 }