delaying working dir creation to when its needed, lazy is sychronised by default

Author: ouchadam

matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/sync/RoomSyncEphemeralTemporaryStore.kt

@@ -39,8 +39,9 @@ internal class RoomSyncEphemeralTemporaryStoreFile @Inject constructor(
         moshi: Moshi
 ) : RoomSyncEphemeralTemporaryStore {
 
-    private val workingDir = File(fileDirectory, "rr")
-            .also { it.mkdirs() }
+    private val workingDir: File by lazy {
+        File(fileDirectory, "rr").also { it.mkdirs() }
+    }
 
     private val roomSyncEphemeralAdapter = moshi.adapter(RoomSyncEphemeral::class.java)