library/src/main/java/com/liulishuo/filedownloader/FileDownloader.java
public int replaceListener(String url, FileDownloadListener listener) {
        return replaceListener(url, FileDownloadUtils.getDefaultSaveFilePath(url), listener);
    }
public int replaceListener(String url, FileDownloadListener listener) {
        return replaceListener(url, FileDownloadUtils.getDefaultSaveFilePath(url), listener);
    }
Find the running task by {@code url} and default path, and replace its listener with
the new one {@code listener}.

@return The target task's DownloadId, if not exist target task, and replace failed, will be 0
@see #replaceListener(int, FileDownloadListener)
@see #replaceListener(String, String, FileDownloadListener)