Move more work off the main thread.

// FREEBIE

SignalServiceKit/src/Messages/OWSReadReceiptManager.m

@@ -178,9 +178,7 @@ NSString *const OWSReadReceiptManagerAreReadReceiptsEnabled = @"areReadReceiptsE
                                                object:nil];
 
     // Try to start processing.
-    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
     [self scheduleProcessing];
-    });
 
     return self;
 }
@@ -198,10 +196,12 @@ NSString *const OWSReadReceiptManagerAreReadReceiptsEnabled = @"areReadReceiptsE
 // Schedules a processing pass, unless one is already scheduled.
 - (void)scheduleProcessing
 {
+    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
         @synchronized(self)
         {
             if ([TSDatabaseView hasPendingViewRegistrations]) {
-            DDLogInfo(@"%@ Deferring read receipt processing due to pending database view registrations.", self.tag);
+                DDLogInfo(
+                    @"%@ Deferring read receipt processing due to pending database view registrations.", self.tag);
                 return;
             }
             if (self.isProcessing) {
@@ -222,6 +222,7 @@ NSString *const OWSReadReceiptManagerAreReadReceiptsEnabled = @"areReadReceiptsE
                     [self process];
                 });
         }
+    });
 }
 
 - (void)process