code: @Override
      public ExtendedSnapshotWriter newSnapshotWriter() throws StorageException {
          checkInitialized();
  
          try {
              return new SnapshotFileWriter(snapshotsDirectory);
          } catch (Exception e) {
              throw new StorageException("fail create snapshot request", e);
          }
      }
docs: {@inheritDoc}
  
  @throws IllegalStateException if this method is called before {@link OnDiskSnapshotsStore#initialize()}