Handle unwrap when shutting down JDC server

..This should prevent the code from panicing if a signal
to shutdown is sent the JDC server

As a result, MAJOR is pumped for `roles-logic-sv2` crate as new property
was added to public `Error` struct.

protocols/v2/roles-logic-sv2/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "roles_logic_sv2"
-version = "1.2.3"
+version = "2.0.0"
 authors = ["The Stratum V2 Developers"]
 edition = "2018"
 description = "Common handlers for use within SV2 roles"

protocols/v2/roles-logic-sv2/src/errors.rs

@@ -113,6 +113,7 @@ pub enum Error {
     LogicErrorMessage(std::boxed::Box<AllMessages<'static>>),
     /// JD server cannot propagate the block due to missing transactions
     JDSMissingTransactions,
+    IoError(std::io::Error),
 }
 
 impl From<BinarySv2Error> for Error {
@@ -121,6 +122,12 @@ impl From<BinarySv2Error> for Error {
     }
 }
 
+impl From<std::io::Error> for Error {
+    fn from(v: std::io::Error) -> Error {
+        Error::IoError(v)
+    }
+}
+
 impl Display for Error {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         use Error::*;
@@ -205,6 +212,7 @@ impl Display for Error {
             HashrateError(e) => write!(f, "Impossible to get Hashrate: {:?}", e),
             LogicErrorMessage(e) => write!(f, "Message is well formatted but can not be handled: {:?}", e),
             JDSMissingTransactions => write!(f, "JD server cannot propagate the block: missing transactions"),
+            IoError(e) => write!(f, "IO error: {:?}", e),
         }
     }
 }

roles/jd-client/src/lib/downstream.rs

@@ -682,7 +682,7 @@ pub async fn listen_for_downstream_mining(
     jd: Option<Arc<Mutex<JobDeclarator>>>,
 ) -> Result<Arc<Mutex<DownstreamMiningNode>>, Error> {
     info!("Listening for downstream mining connections on {}", address);
-    let listner = TcpListener::bind(address).await.unwrap();
+    let listner = TcpListener::bind(address).await?;
 
     if let Ok((stream, _)) = listner.accept().await {
         let responder = Responder::from_authority_kp(

roles/jd-client/src/lib/mod.rs

@@ -337,7 +337,7 @@ impl JobDeclaratorClient {
         };
 
         // Wait for downstream to connect
-        let downstream = downstream::listen_for_downstream_mining(
+        let downstream = match downstream::listen_for_downstream_mining(
             downstream_addr,
             Some(upstream),
             send_solution,
@@ -351,7 +351,10 @@ impl JobDeclaratorClient {
             Some(jd.clone()),
         )
         .await
-        .unwrap();
+        {
+            Ok(d) => d,
+            Err(_e) => return,
+        };
 
         TemplateRx::connect(
             SocketAddr::new(IpAddr::from_str(ip_tp.as_str()).unwrap(), port_tp),