add Entry —> _addModuleChain —> semaphore.acquire —> moduleFactory.create —> addModule —> onModule —> moduleReady —> processModuleDependencies
addEntry(context, entry, name, callback) {const slot = {name: name,module: null};this.preparedChunks.push(slot);this._addModuleChain(context, entry, (module) => {entry.module = module;this.entries.push(module);module.issuer = null;}, (err, module) => {if(err) {return callback(err);}// 保证不重复if(module) {slot.module = module;} else {const idx = this.preparedChunks.indexOf(slot);this.preparedChunks.splice(idx, 1);}return callback(null, module);});}
