Associating HubAction with Parse input

According to the docs:

“When a command method of your device handler returns an instance of a HubAction, the SmartThings platform will use the request information within it to actually perform the request. It will then call the device-handler’s parse method with any response data.”

Fine. But I need a way to associate a particular HubAction call with the response sent to the parse method. I have a bunch of similar HubActions with no reliable way to determine which one a parse call is in response to. Temporal order isn’t reliable, since the requests don’t all take the same amount of time to process.

With the beta asynchronous http request api it looks like you can put a map in the request that will be returned in the response. However, I don’t see anything similar in the hub action. If only the HubAction returned the requestId. . . .