docs: synchronized void requestCompleted(ClientWorldModelInterface worldModel,
        AbstractRequestMessage message) {
      Long ticket = Long.valueOf(message.getTicketNumber());
      log.debug("Request {} completed.", ticket);
  
      Response resp = this.outstandingSnapshots.remove(ticket);
      // Snapshot request
      if (resp != null) {
        log.debug("Retrieved {} for Tix#{}", resp, ticket);
        WorldState ws = this.outstandingStates.get(ticket);
        if (ws == null) {
          log.error("Unknown ticket number {} for request.", ticket, message);
          return;
        }
        resp.setState(ws);
        return;
      }
  
      StepResponse sResp = this.outstandingSteps.remove(ticket);
      // Range/Streaming request
      if (sResp != null) {
        log.debug("Retrieved {} for Tix#{}", resp, ticket);
        sResp.setComplete();
        return;
      }
  
      log.error("Couldn't find response for ticket {}.", ticket);
    }