message:import_scheduling_header(HEADER_NAME, REMOVE)

Reads the header specified and attempts to parse it as JSON-encoded version of the message:set_scheduling() parameters. If successful, it will call message:set_scheduling() with that value, and if REMOVE is set to true, will remove the header from the message.

For example, given this message:

X-Schedule: {"dow":"Mon,Wed","tz":"America/Phoenix","start":"09:00:00","end":"17:00:00"}
Subject: hello

This message should only be delivered during working hours
in Phoenix on Mondays or Wednesdays.

this policy script will parse and remove that header, and apply the scheduling constraints:

kumo.on('smtp_server_message_received', function(msg)
  msg:import_scheduling_header 'X-Schedule'
end)