Metrics not being captured for query

Perhaps search, analytics, views too? I didn't check yet. The issue seems to be this: In the handle's invoke_row call, when is_last is true, we record the http op latency. That seems right, except that the http request object is already destroyed and nulled by then. That happens in the chunk_callback when the req->clear_http_request() call is made.

The similarities to analytics and search suggest maybe same issues there.