/**
* Begin a sync.
*
* <p>The caller is responsible for:
*
* <ul>
* <li>Verifying that any backoffs/minimum next sync requests are respected.
* <li>Ensuring that the device is online.
* <li>Ensuring that dependencies are ready.
* </ul>
*
* @throws AlreadySyncingException
*/
public void start() throws AlreadySyncingException {
if (this.currentState != GlobalSyncStage.Stage.idle) {
throw new AlreadySyncingException(this.currentState);
}
installAsHttpResponseObserver(); // Uninstalled by completeSync or abort.
this.advance();
}
