Stop dereferencing *conn

The *conn pointer returned by newConn is dereferenced in
newDownstreamConn and connectToUpstream (a premature optimization).
As a result, the whole struct is copied and the internal newConn
goroutine works with a different chunk of memory than
downstreamConn and upstreamConn.

downstream.go

@@ -328,7 +328,7 @@ func serverSASLMechanisms(srv *Server) []string {
 }
 
 type downstreamConn struct {
-	conn
+	*conn
 
 	id uint64
 
@@ -363,7 +363,7 @@ func newDownstreamConn(srv *Server, ic ircConn, id uint64) *downstreamConn {
 	options := connOptions{Logger: logger}
 	cm := xirc.CaseMappingASCII
 	dc := &downstreamConn{
-		conn:         *newConn(srv, ic, &options),
+		conn:         newConn(srv, ic, &options),
 		id:           id,
 		nick:         "*",
 		nickCM:       "*",

upstream.go

@@ -191,7 +191,7 @@ type pendingUpstreamCommand struct {
 }
 
 type upstreamConn struct {
-	conn
+	*conn
 
 	network *network
 	user    *user
@@ -353,7 +353,7 @@ func connectToUpstream(ctx context.Context, network *network) (*upstreamConn, er
 
 	cm := stdCaseMapping
 	uc := &upstreamConn{
-		conn:                  *newConn(network.user.srv, newNetIRCConn(netConn), &options),
+		conn:                  newConn(network.user.srv, newNetIRCConn(netConn), &options),
 		network:               network,
 		user:                  network.user,
 		channels:              xirc.NewCaseMappingMap[*upstreamChannel](cm),