CallbacksMedium.kt

//DataRepository.kt, which handles all db handling, where I have passed 3 callbacks, finished, error or maximum tabs reached
public fun addTab(tabModelToInsert: TabModel, 
                  onFinished: (tabModel: TabModel) -> Unit = {}, 
                  onError: (tabModel: TabModel, message: String) -> Unit = { tabModel, message -> }, 
                  onMaxTabReached: (tabModel: TabModel) -> Unit = {}) {
  if (canAddMoreTabs()) {
    val currentMaxId = getCurrentMaxId() ?: 0
      try {
        realm.executeTransaction {
          addTabModelToRealm()
          onFinished(tabModel)
        }
      } catch(e: Exception) {
        onError(tabModelToInsert, e.toString())
        v("Error in inserting tab")
      }
  } else {
     onMaxTabReached(tabModelToInsert)
  }
}

//In Main activity view model
dataRepository?.addTab(tabModel, onFinished = {
                            pageAdapter?.addTab(it)
                        }, onError = { tabModel, error ->
                            FirebaseCrash.log(error)
                        }, onMaxTabReached = {
                            FirebaseAnalytics.getInstance(activity).logEvent("AddingTabsMaxEventReached", null)
                            showSnackbar(view)
                        })