#1033 - Flush all events to server when app enters background

include/mbgl/ios/MGLMapboxEvents.h

@@ -21,4 +21,6 @@
 
 - (void) pushEvent:(NSString *)event withAttributes:(NSDictionary *)attributeDictionary;
 
+- (void) flush;
+
 @end

platform/ios/MGLMapView.mm

@@ -407,10 +407,6 @@ mbgl::DefaultFileSource *mbglFileSource = nullptr;
             email = [NSString stringWithFormat:@"%i", sendMail];
         }
         [evt setValue:email forKey:@"enabled.email"];
-        
-
-
-        
     });
     
     return YES;
@@ -590,6 +586,9 @@ mbgl::DefaultFileSource *mbglFileSource = nullptr;
 
 - (void)appDidBackground:(NSNotification *)notification
 {
+    // Flush Any Events Still In Queue
+    [[MGLMapboxEvents sharedManager] flush];
+    
     mbglMap->stop();
 
     [self.glView deleteDrawable];

platform/ios/MGLMapboxEvents.m

@@ -156,13 +156,17 @@ NSNumber *scale;
         return;
     }
     
+    
+    int upper = (int)_flushAt;
     if (_flushAt > [_queue count]) {
-        NSLog(@"flush() flushAt (%lu) is greater than current queue count (%lu) so just return", _flushAt, [_queue count]);
-        return;
+        if ([_queue count] == 0) {
+            return;
+        }
+        upper = (int)[_queue count];
     }
     
     // Create Array of Events to push to the Server
-    NSRange theRange = NSMakeRange(0, (int)_flushAt);
+    NSRange theRange = NSMakeRange(0, upper);
     NSArray *events = [_queue subarrayWithRange:theRange];
     
     // Update Queue to remove events sent to server