fix: performance regression due to lazy loading the index file

lib/debug.js

@@ -1,15 +1,16 @@
 'use strict'
 
-var index
-function lazyIndex () {
-  return index || require('../')
+var index = {
+  debugMode: /\bredis\b/i.test(process.env.NODE_DEBUG)
 }
+// Lazy load the main file
+process.nextTick(() => (index = require('../')))
 
 /**
  * @description Print a debug statement if in debug mode
  */
 function debug () {
-  if (lazyIndex().debugMode) {
+  if (index.debugMode) {
     console.error.apply(null, arguments)
   }
 }