The default HTTPX timeout of 5 seconds is much too low when communicating with Butler server -- many requests can exceed that while waiting for the database to respond.

Fetching database results for Butler queries can take an unpredictable amount of time, in some cases several minutes.  To ensure that clients do not time out while waiting, send a keep-alive message to the stream every fifteen seconds.

Remove the GzipMiddleware for two reasons:
1. It was preventing "keep-alive" messages from working in streamed responses, because it was batching them until it had a full gzip chunk.
2.  It was slowing down queries by about 10% at the RSP -- it turns out that compressing/decompressing is expensive, and there is lots of bandwidth available within Google.