import: Narrow the id-window to just the current realm.
import: Narrow the id-window to just the current realm.

On multi-realm systems this results in traversal of all messages in
all realms and returns a massive payload of 1 row per stream on 
the server, not the intended one row per realm.
zulip/zulip,zulip/zulip,zulip/zulip,zulip/zulip,zulip/zulip,zulip/zulip,zulip/zulip