Callback method specified at `Sisimai::Message->new` with `hook` is called just before calling `scan()` method of each `Sisimai::Bite::Email` module.
Callback method specified at `Sisimai::Message->new` with `hook` is called just before calling `scan()` method of each `Sisimai::Bite::Email` module.

sisimai/p5-Sisimai