public GfshStopper serverStopper() {
    return new GfshStopper(executor, workingDir, SERVER);
  }
Returns the {@code Stopper} for this {@code GfshExecution}. Provides methods for stopping and
awaiting the termination of server and locator processes that were started using
{@code GfshExecution}.

@return the Stopper for stopping and awaiting processes started by this GfshExecution
geode-junit/src/main/java/org/apache/geode/test/junit/rules/gfsh/GfshExecution.java