private fun <T> Observable<T>.subscribe(onNext:(T)-> Unit = {}, context: KFunction<out Unit>? = null) {
    this.subscribe({}, { ErrorController().onError("[ ${context?.name} ]",it) })
}

//exemple
private fun onReceiveShareAction(userId: String) {
   messenger.sendShareMessage(Recipient(userId)).subscribe(context = ::onReceiveShareAction)
}