Rewrite network protocol/service to use channels (#1340)

* rewrite network protocol/service to use channels

* remove use of unwrap

* re-introduce with_spec

* remove unnecessary mut

* remove unused param

* improve with_spec, add with_gossip

* rename job to task

* style: re-add comma

* remove extra string allocs

* rename use of channel

* turn TODO into FIXME

* remove mut in match

* remove Self in new

* pass headers by value to network service

* remove network sender from service

* remove TODO

* better expect

* rationalize use of network sender in ondemand

substrate/core/network-libp2p/src/traits.rs

@@ -96,21 +96,21 @@ impl NetworkConfiguration {
 }
 
 /// The severity of misbehaviour of a peer that is reported.
-#[derive(Debug, PartialEq, Eq, Clone, Copy)]
-pub enum Severity<'a> {
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub enum Severity {
 	/// Peer is timing out. Could be bad connectivity of overload of work on either of our sides.
 	Timeout,
 	/// Peer has been notably useless. E.g. unable to answer a request that we might reasonably consider
 	/// it could answer.
-	Useless(&'a str),
+	Useless(String),
 	/// Peer has behaved in an invalid manner. This doesn't necessarily need to be Byzantine, but peer
 	/// must have taken concrete action in order to behave in such a way which is wantanly invalid.
-	Bad(&'a str),
+	Bad(String),
 }
 
-impl<'a> fmt::Display for Severity<'a> {
+impl fmt::Display for Severity {
 	fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-		match *self {
+		match self {
 			Severity::Timeout => write!(fmt, "Timeout"),
 			Severity::Useless(r) => write!(fmt, "Useless ({})", r),
 			Severity::Bad(r) => write!(fmt, "Bad ({})", r),