This member is added by an implicit conversion from PeekMailboxExtension to
any2stringadd[PeekMailboxExtension] performed by method any2stringadd in scala.Predef.
This member is added by an implicit conversion from PeekMailboxExtension to
StringFormat[PeekMailboxExtension] performed by method StringFormat in scala.Predef.
(Since version 2.5.0) Use an explicit supervisor or proxy actor instead