code: func (client *Client) StreamGo(serviceMethod string, args interface{}, replyStream interface{}) *Call {
  	// first check the replyStream object is a stream of pointers to a data structure
  	typ := reflect.TypeOf(replyStream)
  	// FIXME: check the direction of the channel, maybe?
  	if typ.Kind() != reflect.Chan || typ.Elem().Kind() != reflect.Ptr {
  		log.Panic("rpc: replyStream is not a channel of pointers")
  		return nil
  	}
  
  	call := new(Call)
  	call.ServiceMethod = serviceMethod
  	call.Args = args
  	call.Reply = replyStream
  	call.Stream = true
  	call.sent = make(chan struct{})
  	call.client = client
  	client.send(call)
  	return call
  }
docs: // Go invokes the streaming function asynchronously.  It returns the Call structure representing
  // the invocation.