iOS 10 don't call Notification Service Extension
<p>I tried to implement the new Notification Service Extension, but I have a problem.</p>

<p>In my NotificationService.swift file I have this code:</p>

<pre><code>class NotificationService: UNNotificationServiceExtension {

var contentHandler: ((UNNotificationContent) -&gt; Void)?
var bestAttemptContent: UNMutableNotificationContent?

override func didReceive(_ request: UNNotificationRequest, withContentHandler contentHandler: @escaping (UNNotificationContent) -&gt; Void) {
    self.contentHandler = contentHandler
    bestAttemptContent = (request.content.mutableCopy() as? UNMutableNotificationContent)

    if let bestAttemptContent = bestAttemptContent {
        // Modify the notification content here...
        bestAttemptContent.title = "\(bestAttemptContent.title) [modified]"

        print(bestAttemptContent.body)

        contentHandler(bestAttemptContent)
    }
}

override func serviceExtensionTimeWillExpire() {
    // Called just before the extension will be terminated by the system.
    // Use this as an opportunity to deliver your "best attempt" at modified content, otherwise the original push payload will be used.
    if let contentHandler = contentHandler, let bestAttemptContent =  bestAttemptContent {
        contentHandler(bestAttemptContent)
    }
}
}
</code></pre>

<p>When I got a push notification the <em>didReceive(_ request: UNNotificationRequest, withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void)</em> method never called. </p>

<p>Maybe I misunderstood how this extension is working?</p>