code: @Override
      public CharSequence get(long timeout, TimeUnit unit) throws ExecutionException {
          try {
              this.futureBuilder.performAppends();
          } catch (IOException | HttpErrorPage e) {
              throw new ExecutionException(e);
          }
          return this.builder.toString();
      }
docs: /*
  (non-Javadoc)
  
  @see java.util.concurrent.Future#get(long, java.util.concurrent.TimeUnit)