You'll tell me how it went

[BloodSweatTears]

What is the best way to ask someone who is going to have an interview to tell us the result of it the next time you see him:

1- You'll tell me how it went.

2- You'll tell me what happened.

 

[Rover_KE]

'Let me know how you got on.'

 

[GoesStation]

In AmE, "Let me know how it went."

 

[emsr2d2]

Let me know how it goes.

 

[BloodSweatTears]

Let me know how it goes.

Why is it appropriates to use the present to talk about something which will have already happened?