This member is added by an implicit conversion from FileBasedMailboxType to
any2stringadd[FileBasedMailboxType] performed by method any2stringadd in scala.Predef.
This member is added by an implicit conversion from FileBasedMailboxType to
StringFormat[FileBasedMailboxType] performed by method StringFormat in scala.Predef.
(Since version 2.3) durable mailboxes are superseded by akka-persistence