code: public List<FutureReadResultEntry> close() {
          List<FutureReadResultEntry> result;
          synchronized (this.reads) {
              if (this.closed) {
                  result = Collections.emptyList();
              } else {
                  result = new ArrayList<>(this.reads);
                  this.reads.clear();
                  this.closed = true;
              }
          }
  
          return result;
      }
docs: Closes this instance of the FutureReadResultEntryCollection class.
  
  @return A List containing all currently registered FutureReadResultEntries.