@Override
 public <D extends Document<?>> Boolean unlock(D document, long timeout, TimeUnit timeUnit) {
   return Blocking.blockForSingle(asyncBucket.unlock(document).single(), timeout, timeUnit);
 }
 @Override
 public Boolean unlock(String id, long cas, long timeout, TimeUnit timeUnit) {
   return Blocking.blockForSingle(asyncBucket.unlock(id, cas).single(), timeout, timeUnit);
 }