使用akka http，我如何将请求头注入到服务器的传入路由中？

import akka.actor.ActorSystem
import akka.http.scaladsl.Http
import akka.http.scaladsl.model.headers.RawHeader
import akka.http.scaladsl.server.Directives._
import akka.http.scaladsl.server.Route

object MyApp extends App {
  implicit val system = ActorSystem("my-system")
  implicit val executionContext = system.dispatcher

  val route: Route = path("myRoute") {
    get {
      headerValueByName("MyHeader") { headerValue =>
        complete(s"The value of MyHeader is: $headerValue")
      }
    }
  }

  val bindingFuture = Http().newServerAt("localhost", 8080).bind(route)

  println(s"Server online at http://localhost:8080/")

  // 等待服务器停止
  bindingFuture.flatMap(_.unbind()).onComplete(_ => system.terminate())
}