docs: private Future<?> sendKeys(final MapStoreContext mapStoreContext, final boolean replaceExistingValues) {
          if (keyLoadFinished.isDone()) {
              keyLoadFinished = new LoadFinishedFuture();
  
              Future<Boolean> sent = execService.submit(MAP_LOAD_ALL_KEYS_EXECUTOR, () -> {
                  sendKeysInBatches(mapStoreContext, replaceExistingValues);
                  return false;
              });
  
              execService.asCompletableFuture(sent).andThen(keyLoadFinished);
          }
  
          return keyLoadFinished;
      }