Quarkus reactive client - sending Multipart from ByteArray

Question

Im trying to use io.quarkus:quarkus-rest-client-reactive-jackson to send a multipart file.

Here is my client class

@RegisterRestClient(configKey = "foo")
interface FooClient {
    @POST
    @Path("/upload")
    fun uploadFile(
        @RestForm("file")
        @PartType("application/octet-stream")
        file: ByteArray
    ): Uni<String>
}

and here is how I invoke it

val file:ByteArray = storage.readAllBytes("foo", "foo")
fooClient.uploadFile(file = file)
              .subscribe()
              .with { log.info("upload file result : $it") }

but I always get internal server error

2022-12-24 03:11:55,135 ERROR [io.qua.mut.run.MutinyInfrastructure] (vert.x-eventloop-thread-0) Mutiny had to drop the following exception: org.jboss.resteasy.reactive.ClientWebApplicationException: Received: 'Internal Server Error, status code 500' when invoking: Rest Client method: 'foo.FooClient#uploadFile'

How to send a multipart file with ByteArray in quarkus reactive?