didBecomeActive kicks the processing queue

// FREEBIE

Signal/src/AppDelegate.m

@@ -517,6 +517,9 @@ static NSString *const kURLHostVerifyPrefix             = @"verify";
                 // This will fetch new messages, if we're using domain
                 // fronting.
                 [[PushManager sharedManager] applicationDidBecomeActive];
+
+                // If there were any messages in our local queue which we hadn't yet processed.
+                [[OWSMessageReceiver sharedInstance] handleAnyUnprocessedEnvelopes];
             }];
 
     DDLogInfo(@"%@ applicationDidBecomeActive completed.", self.tag);

SignalServiceKit/src/Messages/OWSMessageReceiver.h

@@ -13,6 +13,7 @@ NS_ASSUME_NONNULL_BEGIN
 + (void)syncRegisterDatabaseExtension:(YapDatabase *)database;
 
 - (void)handleReceivedEnvelope:(OWSSignalServiceProtosEnvelope *)envelope;
+- (void)handleAnyUnprocessedEnvelopes;
 
 @end
 

SignalServiceKit/src/Messages/OWSMessageReceiver.m

@@ -351,6 +351,11 @@ NSString *const OWSMessageProcessingJobFinderExtensionGroup = @"OWSMessageProces
 
 #pragma mark - instance methods
 
+- (void)handleAnyUnprocessedEnvelopes
+{
+    [self.processingQueue drainQueue];
+}
+
 - (void)handleReceivedEnvelope:(OWSSignalServiceProtosEnvelope *)envelope
 {
     // Drop any too-large messages on the floor. Well behaving clients should never send them.