* to the string returned by {@link #serviceName}
   */
  protected Executor executor() {
    return command -> newThread(serviceName(), command).start();
  }

  @Override
  public String toString() {
    return serviceName() + " [" + state() + "]";
  }

  @Override
  public final boolean isRunning() {
    return delegate.isRunning();
  }

        sv.setUpdated("20200710072412");
        target.getVersioning().addSnapshotVersion(sv);

        Metadata source = createMetadataFromArtifact(artifact);
        // nothing should be actually changed, but still merge returns true
        assertTrue(target.merge(source));

        // NOTE! Merge updates last updated to source
        assertEquals("20200921071745", source.getVersioning().getLastUpdated());

        return ((Map<?, ?>) value).isEmpty();
      } else if (value instanceof java.util.Optional) {
        return !((java.util.Optional<?>) value).isPresent();
      } else if (value instanceof OptionalInt) {
        return !((OptionalInt) value).isPresent();
      } else if (value instanceof OptionalLong) {
        return !((OptionalLong) value).isPresent();
      } else if (value instanceof OptionalDouble) {

      return var.toString();
    }

    /** Wraps {@code t} in a {@code TypeVariableKey} if it's a type variable. */
    static @Nullable TypeVariableKey forLookup(Type t) {
      if (t instanceof TypeVariable) {
        return new TypeVariableKey((TypeVariable<?>) t);
      } else {
        return null;
      }
    }

    /**

     */
    void store(DataStoreParams paramMap, Map<String, Object> dataMap);

    /**
     * Returns the total number of documents processed by this callback.
     *
     * @return the document count
     */
    long getDocumentSize();

    /**
     * Returns the total execution time for index update operations.
     *
     * @return the execution time in milliseconds
     */
    long getExecuteTime();

    /**

  /** Constructor for use by subclasses. */
  protected Ticker() {}

  /** Returns the number of nanoseconds elapsed since this ticker's fixed point of reference. */
  public abstract long read();

  /**
   * A ticker that reads the current time using {@link System#nanoTime}.
   *
   * @since 10.0
   */
  public static Ticker systemTicker() {
    return SYSTEM_TICKER;
  }

  private static final Ticker SYSTEM_TICKER =

      return bigDecimal.doubleValue();
    }

    @Override
    int sign(BigDecimal bigDecimal) {
      return bigDecimal.signum();
    }

    @Override
    BigDecimal toX(double d, RoundingMode mode) {
      return new BigDecimal(d);
    }

    @Override
    BigDecimal minus(BigDecimal a, BigDecimal b) {
      return a.subtract(b);
    }
  }

      return graph.predecessors(node);
    } else {
      return ImmutableSet.of();
    }
  }

  /**
   * Returns the successors of the given node, or an empty set if this set does not represent
   * outgoing edges.
   */
  private Set<N> successorsOrEmpty(N node) {
    if (edgeType == EdgeType.OUTGOING || edgeType == EdgeType.BOTH) {
      return graph.successors(node);
    } else {

	if err != nil {
		return 0, err
	}
	_, err = b.Hash.Write(p)
	if err != nil {
		return 0, err
	}
	return len(p), nil
}

func (b *wholeBitrotWriter) Close() error {
	return nil
}

// Returns whole-file bitrot writer.
func newWholeBitrotWriter(disk StorageAPI, volume, filePath string, algo BitrotAlgorithm, shardSize int64) io.WriteCloser {

}

// RLockedOpenFile - returns a wrapped read locked file, if the file
// doesn't exist at path returns an error.
func RLockedOpenFile(path string) (*RLockedFile, error) {
	lkFile, err := LockedOpenFile(path, os.O_RDONLY, 0o666)
	if err != nil {
		return nil, err
	}

	return newRLockedFile(lkFile)
}

// LockedFile represents a locked file
type LockedFile struct {
	*os.File