code: @Override
      public IBucket read(final long pKey) throws TTIOException {
          Future<IBucket> secondReturn = mService.submit(new Callable<IBucket>() {
              @Override
              public IBucket call() throws Exception {
                  return mSecondWriter.read(pKey);
              }
          });
          IBucket returnVal = mFirstWriter.read(pKey);
          try {
              if (returnVal == null) {
                  return secondReturn.get();
              } else {
                  return returnVal;
              }
          } catch (ExecutionException | InterruptedException exc) {
              throw new TTIOException(exc);
          }
      }
docs: {@inheritDoc}