`rack.hijack` looks like a way to do streaming. It's really a way out of the Rack contract: the application takes the socket, and with it all the bookkeeping the server was doing on its behalf. Two kinds of hijack, and only one of them frees a thread.
icofon takes a folder of SVGs and builds an icon font, a stylesheet and a preview page. What happens to a drawing on its way from SVG to glyph, where the tool runs into the limits of the format, and why codepoints can't be handed out fresh on every build.
Lifting a constraint costs almost nothing; adding one after the fact is expensive — first an investigation, then a placeholder that outlives everyone. On starting narrow and widening on demand.
