vscode: Cannot send events as part of extension deactivation

If extensions send events as part of deactivate, awaiting disposal of the telemetry reporter exceeds the 4s shutdown limit for extensions, so these events aren’t sent.

Repro extension: repro.zip

extension.ts:

import * as vscode from 'vscode';
import * as fs from 'fs';
import TelemetryReporter from 'vscode-extension-telemetry';

let reporter: TelemetryReporter;
let sendEventOnDispose = true;

export function activate(context: vscode.ExtensionContext) {
	reporter = new TelemetryReporter('extension', '0.0.0', 'my-key');
}

export async function deactivate() {
	fs.writeFileSync('/start.txt', ''); 
	if (sendEventOnDispose) {
		reporter.sendTelemetryEvent('event');
	}
	await reporter.dispose();
	fs.writeFileSync('/end.txt', ''); 
}

If sendEventOnDispose is true, the extension never completes deactivating (end.txt isn’t created). If sendEventOnDispose is false, deactivation completes.