int getDegreeOfConcurrency();

    @Nonnull
    Instant getStartTime();

    /**
     * Gets the directory of the topmost project being built, usually the current directory or the
     * directory pointed at by the {@code -f/--file} command line argument.
     */
    @Nonnull
    Path getTopDirectory();

    /**
     * Gets the root directory of the session, which is the root directory for the top directory project.

Offline Mode Design

* UPDATE: 18-April-2005

  We cannot take the approach outlined below of detecting which remote
  repositories are "really" offline, since offline mode is more of a behavior,
  and this will lead to counter-intuitive results. A different feature may exist
  unimplemented, which is to detect when the network is down and provide better
  feedback for that case. However, when offline mode is declared, nothing

     * @since 4.0.0
     */
    MavenExecutionRequest setTopDirectory(Path topDirectory);

    /**
     * Gets the directory of the topmost project being built, usually the current directory or the
     * directory pointed at by the {@code -f/--file} command line argument.
     *
     * @since 4.0.0
     */
    Path getTopDirectory();

    /**
     * Sets the root directory of the project.
     *
     * @since 4.0.0