fn find_registered_tube<'a>(
registered_tubes: &'a HashMap<RegisteredEvent, HashSet<AddressedProtoTube>>,
socket_addr: &str,
event: RegisteredEvent
) -> (Option<&'a Rc<ProtoTube>>, bool)
fn find_registered_tube<'a>(
registered_tubes: &'a HashMap<RegisteredEvent, HashSet<AddressedProtoTube>>,
socket_addr: &str,
event: RegisteredEvent
) -> (Option<&'a Rc<ProtoTube>>, bool)