Process is used to start new processes using the static start and run methods.

class Process {
  /**
   * Starts a process running the [executable] with the specified
   * [arguments]. Returns a [:Future<Process>:] that completes with a
   * Process instance when the process has been successfully
   * started. That [Process] object can be used to interact with the
   * process. If the process cannot be started the returned [Future]
   * completes with an exception.
   *
   * An optional [ProcessOptions] object can be passed to specify
   * options other than the executable and the arguments.
   */
  static Future<Process> start(String executable,
                               List<String> arguments,
                               [ProcessOptions options]) {
    return _Process.start(executable, arguments, options);
  }

  /**
   * Starts a process and runs it non-interactively to completion. The
   * process run is [executable] with the specified [arguments].
   *
   * An optional [ProcessOptions] object can be passed to specify
   * options other than the executable and the arguments.
   *
   * Returns a [:Future<ProcessResult>:] that completes with the
   * result of running the process, i.e., exit code, standard out and
   * standard in.
   */
  static Future<ProcessResult> run(String executable,
                                   List<String> arguments,
                                   [ProcessOptions options]) {
    return _Process.run(executable, arguments, options);
  }

  /**
   * Returns an input stream of the process stdout.
   *
   * Throws an [UnsupportedOperationException] if the process is
   * non-interactive.
   */
  abstract InputStream get stdout;

  /**
   * Returns an input stream of the process stderr.
   *
   * Throws an [UnsupportedOperationException] if the process is
   * non-interactive.
   */
  abstract InputStream get stderr;

  /**
   * Returns an output stream to the process stdin.
   *
   * Throws an [UnsupportedOperationException] if the process is
   * non-interactive.
   */
  abstract OutputStream get stdin;

  /**
   * Sets an exit handler which gets invoked when the process
   * terminates.
   *
   * Throws an [UnsupportedOperationException] if the process is
   * non-interactive.
   */
  abstract void set onExit(void callback(int exitCode));

  /**
   * On Windows, [kill] kills the process, ignoring the [signal]
   * flag. On Posix systems, [kill] sends [signal] to the
   * process. Depending on the signal giving, it'll have different
   * meanings. When the process terminates as a result of calling
   * [kill] [onExit] is called.
   *
   * Returns [:true:] if the process is successfully killed (the
   * signal is successfully sent). Returns [:false:] if the process
   * could not be killed (the signal could not be sent). Usually,
   * a [:false:] return value from kill means that the process is
   * already dead.
   */
  abstract bool kill([ProcessSignal signal = ProcessSignal.SIGTERM]);

  /**
   * Terminates the streams of a process. [close] must be called on a
   * process to free the system resources associated with it if not all
   * data on the stdout and stderr streams have been read. Usually,
   * close should be called in [onExit], but care must be taken to actually
   * wait on the stderr and stdout streams to close if all data is required.
   * Once a process has been closed it can no longer be killed and [onExit]
   * is detached so the application is not notified of process termination.
   */
  abstract void close();
}