Die Bildung der Verlaufsform des vollendeten Futurs (= Futur II, Futur Perfekt) erfolgt, indem man das vollendete Futur von to be + Verb + Endung -ing verbindet.

Bildung des Futur II im Englischen
to will + have + Partizip II von to be + Verb + ing
I will have been do ing I will have been doing my homework
you will have been go ing You will have been going to London
he will have been eat ing He will have been eating his soup.
we will have been com ing We will have been coming to your house.
you will have been ask ing You will have been asking a higher price.
they will have been leav ing They will have been leaving for their holidays.