Call NetworkService::add_known_address before sending a request (#2726)

* Call NetworkService::add_known_address before sending a request

* Better doc

* Update Substrate

* Update Substrate

* Restore the import 🤷‍♀️ I don't know why it compiles locally

* imports correctly

Co-authored-by: Robert Habermeier <rphmeier@gmail.com>

polkadot/node/network/protocol/src/request_response/request.rs

@@ -90,6 +90,12 @@ pub enum Recipient {
 ///
 /// The network implementation will make use of that sender for informing the requesting subsystem
 /// about responses/errors.
+///
+/// When using `Recipient::Peer`, keep in mind that no address (as in IP address and port) might
+/// be known for that specific peer. You are encouraged to use `Peer` for peers that you are
+/// expected to be already connected to.
+/// When using `Recipient::Authority`, the addresses can be found thanks to the authority
+/// discovery system.
 #[derive(Debug)]
 pub struct OutgoingRequest<Req> {
 	/// Intendent recipient of this request.