What's missing from sgload

- Ramp up
- Stability (72 hour test, RAM usage, etc)
- Time based run (it's currently doc based)
- Logging doc read/write failures
- Round trip time when shows up on changes (currently only when shows up on bulk_get) -- would have to put the timestamp in the docid, or maintain a map
- Add `--readerdelayms` -- runs for a certain amount of time, closes changes feed, restarts changes feed. Adjusts round trip time based time you were asleep. NOTE: gateload doesn't use this in standard tests.
- `feed=continuous`

- Channel access grants via Sync Function (missing from both)
- Sticky sessions (missing from both)
- Changing load settings mid-run (missing from both)
- Blip over websockets based push/pull for CouchbaseLite 2.0 (missing from both)
- Role support. Admin API grant or Doc function grant (missing from both)