Sometimes, you will have to face a situation where you will be sure that the object will not be null at the time of accessing it. However, since you have declared nullable at the beginning, you will have to end up using force unwraps. Force unwraps have the syntax of !!. This means you have to fetch the value of the calling object, irrespective of it being nullable. We are explicitly reading the chatMessage value to pass its value in the callback. The following is the code:
callback(chatMessage!!)
Force unwraps are something we should avoid. We should only use them while dealing with interoperability issues. Otherwise, using them is basically nothing but throwing away Kotlin's beautiful features.
