code: public void index(final ByteBuffer key, final ColumnFamily columnFamily, final long timestamp) {
          if (indexQueue == null) {
              indexInner(key, columnFamily, timestamp);
          } else {
              indexQueue.submitAsynchronous(key, new Runnable() {
                  @Override
                  public void run() {
                      indexInner(key, columnFamily, timestamp);
                  }
              });
          }
      }
docs: Indexes the logical {@link Row} identified by the specified key and column family using the specified time stamp.
  The must be read from the {@link ColumnFamilyStore} because it could exist previously having more columns than
  the specified ones. The specified {@link ColumnFamily} is used for determine the cluster key. This operation is
  performed asynchronously.
  
  @param key          A partition key.
  @param columnFamily A {@link ColumnFamily} with a single common cluster key.
  @param timestamp    The insertion time.