Future perfect continuous verbs: These are verbs that are happening in the future, however they are ongoing and are not completed.

An action happening before another future action:

"When you'll arrive, I will have been reading for two hours already."

Relationship between two future actions:

"I'm going to be really happy tomorrow because I will be visiting the downtown parade."

"By the time I retire, I will have been a teacher for over 50 years."