Available from version 1.14.0
Called in Setup.php, after cache objects are set
Define function:
public static function onSetupAfterCache(   ) { ... }
Attach hook: In extension.json:
	"Hooks": {
		"SetupAfterCache": "MyExtensionHooks::onSetupAfterCache"
Called from: File(s): Setup.php
Interface: SetupAfterCacheHook.php

For more information about attaching hooks, see Manual:Hooks .
For examples of extensions using this hook, see Category:SetupAfterCache extensions.

SetupAfterCache should only be used for initialization that actually needs to run right after $wgMemc stuff is created. Everything else should use $wgExtensionFunctions. If you need to use the RequestContext, consider BeforeInitialize and ApiBeforeMain hooks instead.