private static String tryOpenFileWithDirectIO(String path) {
        File file = new File(path);
        try {
            DirectRandomAccessFile randomAccessFile = new DirectRandomAccessFile(file, "rw");
            randomAccessFile.close();
            return null;
        } catch (IOException e) {
            return e.getMessage();
        } finally {
            // the file may be created in {@link DirectRandomAccessFile(File, String)}, so delete it
            file.delete();
        }
    }
Try to open a file with O_DIRECT flag to check whether the file system supports O_DIRECT.
The file will be deleted after the test.

@return null if the file is opened successfully, otherwise the reason why it's not available
s3stream/src/main/java/com/automq/stream/s3/wal/util/WALBlockDeviceChannel.java