public Long rPush(byte[] key, byte[] value) {
   try {
     if (isPipelined()) {
       pipeline(pipeline.rpush(key, new Object[] {value}));
       return null;
     }
     return client.rpush(key, new Object[] {value}).data();
   } catch (Exception ex) {
     throw convertSrpAccessException(ex);
   }
 }