Managing multiple Observables in RxJava

It is necessary to build a reactive chain that, when a button is pressed, reads a string, converts it into a Car object, and sends a request to the server. When a new request appears, the previous one should be canceled to avoid unnecessary network operations.

val clickStream: Observable<String>? = null
val clickStream1: Observable<String>? = null
val clickStream2: Observable<String>? = null

data class Car(
    val name: String
)