Shared Native instance of worker and main thread - nativescript

Question

I want to make a progressbar file download. Calculation of an already loaded file needs to be done in a separate thread. That's just not clear how to pass a variable manager
main.js
import * as MyWorker from 'nativescript-worker-loader!~/utils/DownloadManagerProgress.js';
const { DOWNLOAD_SERVICE } = android.content.Context;
const manager = app.android.context.getSystemService(DOWNLOAD_SERVICE);
const worker = new MyWorker();
worker.postMessage({ manager });
worker.onmessage = function (event) {
console.log(event);
};
worker.onerror = function (err) {
console.log(`An unhandled error occurred in worker: ${err.filename}, line:
${err.lineno} :`);
console.log(err.message);
};
DownloadManagerProgress.js
import 'globals';
global.onmessage = (msg) => {
const { manager } = msg.data;
const query = new android.app.DownloadManager.Query();
const cursor = manager.query(query);
};
Error:
'Uncaught TypeError: Cannot read property \'query\' of undefined'
If I create an object in the worker, an error also appears
DownloadManagerProgress.js
import 'globals';
import * as app from 'application';
global.onmessage = (msg) => {
const { DOWNLOAD_SERVICE } = android.content.Context;
const manager = app.android.context.getSystemService(DOWNLOAD_SERVICE);
const query = new android.app.DownloadManager.Query();
const cursor = manager.query(query);
};
error:
Uncaught TypeError: Cannot read property \'getSystemService\' of undefined'
Сould help me. Thanks.