JSON.stringify({id, event: line}) treated the already-JSON `line` as a
plain string, so every event landed in the hub double-encoded (a JSON
string containing escaped JSON, not an object) -- agent-console's
json.Unmarshal into a struct silently failed on every single event.
Now the raw JSON line is spliced directly into the request body.
Also await all in-flight event posts before posting /agent/end, since
those POSTs were fire-and-forget and could reorder past it on the wire.
Story Crater Bot
83efe8ef9e