event: response.created
data: {"type":"response.created","response":{"id":"resp1"}}

event: response.output_item.done
data: {"type":"response.output_item.done","item":{"type":"message","role":"assistant","content":[{"type":"output_text","text":"fixture hello"}]}}

event: response.completed
data: {"type":"response.completed","response":{"id":"resp1","output":[]}}