Pure restart of the embedded broker is not advisable, since it's state could be corrupted. Therefore, you're advised to instantiate the broker again before restarting it.
In 5.3 however, we allowed the force start of the broker that has been stopped for use cases that need this functionality. You can do it by using
The following example demonstrates it.
However, it's better (more reliable) to instantiate the broker again if it is possible.