src/vs/platform/windows/electron-main/windowsMainService.ts/WindowsMainService/sendToAll
class WindowsMainService:	sendToAll(channel: string, payload?: any, windowIdsToIgnore?: number[]): void {
		for (const window of this.getWindows()) {
			if (windowIdsToIgnore && windowIdsToIgnore.indexOf(window.id) >= 0) {
				continue; // do not send if we are instructed to ignore it
			}

			window.sendWhenReady(channel, CancellationToken.None, payload);
		}
	}