minor code change causes stream to block

hi,

i've been using async-std for some time now and I think I might have hit a bug.

my code is here https://gitlab.ensimag.fr/wagnerf/listen/-/tree/blocking

(it is on the "blocking" branch)

if you launch it right now (cargo run) it's fine : you can use left/up arrows in the graphical menu to select an entry.

now, in src/video/tune_selector.rs
if you comment line 84 and uncomment line 85 suddenly the keyboard event stream becomes unresponsive. you cannot select anything anymore in the menu.

it is surprising for me because the changes between the working and non-working version are really really minor.

what's more it means touching the video frames stream makes the keyboard events stream stall.

i'm not sure where to go from there, so any help would be appreciated.

note that i can postpone this modification, so there is no emergency for me.