Function shared_agent 

pub(crate) fn shared_agent() -> Agent

The sharing’s server’s one agent in this process (remote::Server): its connections and TLS sessions kept between the requests of a pull, of the sends after it and of the next pull, so that a phone’s step opens one connection, not one per pull, per send and per file sent (on mobile data, each new one wakes the radio for a TLS handshake). Each request says its own budget (its whole and its connection’s time, configure_request; its stall, stalls::ask); ureq keeps an idle connection fifteen seconds.