lookup t channel is
Some (expiry, translated_channel) - the new endpoints that should be applied to a packet using
channel - or
None if no entry for
expiry is an absolute time-stamp.
insert t ~expiry translations adds the given translations to the table. Each translation is a pair
input, target - packets with channel
input should be rewritten to have channel
output. It returns an error if the new entries would overlap with existing entries.
expiry is the absolute time-stamp of the desired expiry time.