In the new socket server code, clojure.core.server is proactively loaded (regardless of whether servers are in the config), which will also load clojure.edn and clojure.string.
Approach: Delay loading of this code until the first server config is found. This improves startup time when not using the socket server about 0.05 s.
Bump. With the introduction of Spec, and considering the fact that clojure.core.server triggers the initialization of Spec, the benefit of solving this issue should now be bigger than 0.05 sec (more like 0.2 sec). See http://clojure-goes-fast.com/blog/clojures-slow-start .