CR: add debug asserts

Signal/src/ViewControllers/ConversationView/ConversationViewModel.m

@@ -602,6 +602,10 @@ static const int kYapDatabaseRangeMinLength = 0;
     }
 
     for (TSOutgoingMessage *unsavedOutgoingMessage in self.unsavedOutgoingMessages) {
+        // unsavedOutgoingMessages should only exist for a short period (usually 30-50ms) before
+        // they are saved and moved into the `persistedViewItems`
+        OWSAssertDebug(
+            unsavedOutgoingMessage.timestampForSorting >= ([NSDate ows_millisecondTimeStamp] - 1 * kSecondInMs));
         NSUInteger index = [rowChanges indexOfObjectPassingTest:^BOOL(
             YapDatabaseViewRowChange *_Nonnull rowChange, NSUInteger idx, BOOL *_Nonnull stop) {
             return [rowChange.collectionKey.key isEqualToString:unsavedOutgoingMessage.uniqueId];

SignalMessaging/utils/ThreadUtil.m

@@ -83,7 +83,7 @@ NS_ASSUME_NONNULL_BEGIN
                                      quotedMessage:[quotedReplyModel buildQuotedMessageForSending]];
 
     [BenchManager benchAsyncWithTitle:@"Saving outgoing message" block:^(void (^benchmarkCompletion)(void)) {
-        // To avoid blocking the send flow, we disapatch an async write from within this read transaction
+        // To avoid blocking the send flow, we dispatch an async write from within this read transaction
         [self.dbConnection asyncReadWriteWithBlock:^(YapDatabaseReadWriteTransaction * _Nonnull writeTransaction) {
             [message saveWithTransaction:writeTransaction];
             [self.messageSenderJobQueue addMessage:message transaction:writeTransaction];