SearchFragment.kt

    val subject = PublishSubject.create<String>()

    search_edit_text.addTextChangedListener(object : TextWatcher {
        override fun afterTextChanged(s: Editable?) {
                subject.onNext(s.toString())
        }

        override fun beforeTextChanged(s: CharSequence?, start: Int, count: Int, after: Int) {
        }

        override fun onTextChanged(s: CharSequence?, start: Int, before: Int, count: Int) {
        }
    })

    presenter.search(subject)