Transient name display

If you press 'n' in the visual mode, you are expected to see names instead of IP addresses. However, at least on my MacOS run, and having many connections, it shows up the names as flashing occasionally, and mostly with addresses. For the same connections. Why?

Start by reproducing the visual mode behavior on macOS with many connections, using the 'n' key to toggle name display. Trace the visual-mode path that switches between names and IP addresses; done means names remain consistently displayed for the same connections instead of flashing intermittently.

Written by the indexing model from the issue text.