refactor(client): change retryable request future from boxed to 'impl Future'
refactor(client): change retryable request future from boxed to 'impl Future'

tshepang/hyper,hyperium/hyper,hyperium/hyper,hyperium/hyper,yazaddaruvala/hyper,yazaddaruvala/hyper,tshepang/hyper,tshepang/hyper