code: @Override
    public OperationFuture<CASResponse>
    asyncCAS(String key, long casId, Object value) {
      return asyncCAS(key, casId, value, transcoder);
    }
docs: Asynchronous CAS operation using the default transcoder.
  
  @param key the key
  @param casId the CAS identifier (from a gets operation)
  @param value the new value
  @return a future that will indicate the status of the CAS
  @throws IllegalStateException in the rare circumstance where queue is too
  full to accept any more requests