Add display method with message, duration and completion block

CWStatusBarNotification/CWStatusBarNotification.h

@@ -208,6 +208,21 @@ typedef NS_ENUM(NSInteger, CWNotificationAnimationType) {
 - (void)displayNotificationWithMessage:(NSString *)message
                            forDuration:(NSTimeInterval)duration;
 
+/**
+ * Displays a notification with the indicated message for the indicated
+ * duration and then performs the completion block once the notification animates in.
+ * @param message
+ *        The content of the message to be displayed.
+ * @param duration
+ *        The amount of seconds for which the notification should be displayed,
+ *        not including the animate in and out times.
+ * @param completion
+ *        The block to be invoked once the notification is displayed.
+ */
+- (void)displayNotificationWithMessage:(NSString *)message
+                           forDuration:(NSTimeInterval)duration
+                            completion:(void (^)(void))completion;
+
 /**
  * Displays a notification with the indicated attributed string and then 
  * performs the completion block once the notification animates in.

CWStatusBarNotification/CWStatusBarNotification.m

@@ -106,6 +106,7 @@ @interface CWViewController()
 
 @implementation CWViewController
 
+@synthesize preferredStatusBarStyle = _preferredStatusBarStyle;
 - (UIStatusBarStyle)preferredStatusBarStyle
 {
     return _preferredStatusBarStyle;
@@ -512,6 +513,15 @@ - (void)displayNotificationWithMessage:(NSString *)message forDuration:(NSTimeIn
     }];
 }
 
+- (void)displayNotificationWithMessage:(NSString *)message forDuration:(NSTimeInterval)duration completion:(void (^)(void))completion
+{
+    [self displayNotificationWithMessage:message completion:^{
+        self.dismissHandle = perform_block_after_delay(duration, ^{
+            [self dismissNotificationWithCompletion:completion];
+        });
+    }];
+}
+
 - (void)displayNotificationWithAttributedString:(NSAttributedString *)attributedString completion:(void (^)(void))completion
 {
     [self displayNotificationWithMessage:[attributedString string] completion:completion];