[scalaz-stream] How to implement an ask then wait for reply pattern

[jilen nil]

StackOverFlow link

I want to implement an client app that first send an request to server then wait for its reply(similar to http)

My client process may be

val topic = async.topic[ByteVector] 
val client = topic.subscribe

Here is the Client 

trait Client {
  val topic = async.topic[ByteVector] 
  val client = topic.subscribe
  val incoming = tcp.connect(...)(client) 
  val reqBus = topic.pubsh() 
  def ask(req: ByteVector): Task[Throwable \/ ByteVector] = { 
     (tcp.writes(req).flatMap(_ => tcp.reads(1024))).to(reqBus) 
     ??? 
  } 
}


How to implement the remaining part