public Song call() throws Exception {
concurrentJobsSemaphore.acquire();
try {
bus.post(new DownloadSongStartedEvent(this, song));
File tempFile = new File(tempPath,
syncFile.getName() + SyncService.TEMP_FILE_EXTENSION_1);
File tempFile2 = new File(tempPath,
syncFile.getName() + SyncService.TEMP_FILE_EXTENSION_2);