code: public List<TempBlockMeta> getSessionTempBlocks(long sessionId) {
      List<TempBlockMeta> sessionTempBlocks = new ArrayList<>();
      for (StorageTier tier : mTiers) {
        for (StorageDir dir : tier.getStorageDirs()) {
          sessionTempBlocks.addAll(dir.getSessionTempBlocks(sessionId));
        }
      }
      return sessionTempBlocks;
    }
docs: Gets all the temporary blocks associated with a session, empty list is returned if the session
  has no temporary blocks.
  
  @param sessionId the id of the session
  @return A list of temp blocks associated with the session