title: Sequence Diagram - Friendship request FCM
body: <p>I am creating the Sequence diagram that represents sending friendship requests from User 1 to user 2. The requests are stored in Firebase Realtime Database. User 2 is notified by Firebase Cloud Messaging that subscribes to topic which is user id. User 2 can deny or accept the request. This scenario I would like to model by sequence diagram. I have created this diagram so far. I am not sure how to capture action 1.1. After logging FCM is subscribed to user id. How would you model accept or deny of the request?</p>
  
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