This was an oversight on my part from before. I didn't check if the internals of an HttpClient object were already destroyed when destroying it. But if it has errored, it will have already cleaned up its internals. So if a request errored and you then ran `httpClientDestroy()` (as you should), you would cause that horrible `Data structure with index does not exist.` error. This should stop people getting that when they lack an internet connection.