src/vs/workbench/services/extensions/common/extensions.ts/ExtensionIdentifierSet/forEach
class ExtensionIdentifierSet:	forEach(callbackfn: (value: ExtensionIdentifier, value2: ExtensionIdentifier, set: Set<ExtensionIdentifier>) => void, thisArg?: any): void {
		this._map.forEach(value => callbackfn.call(thisArg, value, value, this));
	}