is the actor whose preRestart() hook failed
is the exception thrown by that actor within preRestart()
is the message which was optionally passed into preRestart()
is the exception which caused the restart in the first place
(Since version 2.11.0) Use Throwable#getStackTrace
A PreRestartException is thrown when the preRestart() method failed; this exception is not propagated to the supervisor, as it originates from the already failed instance, hence it is only visible as log entry on the event stream.