Serializer for class '...' is not found. ktor + kotlinx.serialization - kotlin

Question

I am using ktor + kotlinx.serialization and i want to achieve a json response from call.respond(Respond("some mesage",null)) something like this :
when result = null
{ "message" : "some mesage" }
when result is any Type
{
"message" : "some mesage",
"result" : "showing result"
}
or
{
"message" : "some mesage",
"result" : 0.0
}
my Respond data class
#kotlinx.serialization.Serializable
data class Respond<T>(
#SerialName("message")
val message : String? = null,
#SerialName("result")
val result : T? = null
)
but it giving me an error like this :
Serializer for class 'Respond' is not found.
Mark the class as #Serializable or provide the serializer explicitly.

Answer 1

I achieved by create inheritance of BaseResponse then polymorphism Response that override type of result with nullable String :
#kotlinx.serialization.Serializable
sealed class BaseResponse<T> {
abstract val message: String?
abstract val result: T?
}
#kotlinx.serialization.Serializable
#SerialName("Response")
class Response(
#SerialName("message") override val message: String?, override val result: String? = null
) : BaseResponse<String>()
#kotlinx.serialization.Serializable
#SerialName("FullResponse")
class FullBaseResponse<T>(
#SerialName("message") override val message: String?, override val result: T
) : BaseResponse<T>()
val responseModule = SerializersModule {
polymorphic(BaseResponse::class) {
subclass(Response.serializer())
subclass(FullBaseResponse.serializer(PolymorphicSerializer(Any::class)))
}
}
and added json configuration :
install(ContentNegotiation) {
json(Json {
explicitNulls = false
serializersModule = responseModule
})
}
so now I just use call.respond(Respond("some message")) when I only want to show message