func ohno(h2client *http2.ClientConn)

     pr, pw := io.Pipe()
  
      ctx, cancel := context.WithCancel(context.Background())
      defer cancel()
  
      var completed = false
      go func () {
          time.Sleep(5*time.Second)
          if !completed {
              //FIXME this does nothing
              cancel();
          }   
      }() 
  
      req, err := http.NewRequestWithContext(ctx, "POST", "https://some/url", pr) 
      if err != nil { panic(err) }
  
      rsp, err := h2client.RoundTrip(req)
      if err != nil { panic(err) }

      completed = true
}