src/vs/workbench/api/common/extHostDebugService.ts/ExtHostDebugServiceBase/registerDebugAdapterTrackerFactory
class ExtHostDebugServiceBase:	public registerDebugAdapterTrackerFactory(type: string, factory: vscode.DebugAdapterTrackerFactory): vscode.Disposable {

		if (!factory) {
			return new Disposable(() => { });
		}

		const handle = this._trackerFactoryHandleCounter++;
		this._trackerFactories.push({ type, handle, factory });

		return new Disposable(() => {
			this._trackerFactories = this._trackerFactories.filter(p => p.factory !== factory);		// remove
		});
	}