Khttp android app stopped

hi
when i used khttp library my app be stopped after click on button

import khttp.* - ide show me mess “unused import directive” what is mean?

code:

            val headerFT = mapOf("User-Agent" to "Mozilla/5.0 (Linux; Android 6.0; Nexus 5 Build/MRA58N) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.130 Mobile Safari/537.36")
                val dataFT = mapOf("email" to email.text.toString(), "password" to password.text.toString())
val response = khttp.post(url="urlapi", data=dataFT,headers = headerFT)