Fix SplitHTTP Unix domain socket (#3577)

Co-authored-by: mmmray <142015632+mmmray@users.noreply.github.com>

transport/internet/splithttp/splithttp_test.go

@@ -298,3 +298,65 @@ func Test_listenSHAndDial_QUIC(t *testing.T) {
 		t.Error("end: ", end, " start: ", start)
 	}
 }
+
+func Test_listenSHAndDial_Unix(t *testing.T) {
+	tempDir := t.TempDir()
+	tempSocket := tempDir + "/server.sock"
+
+	listen, err := ListenSH(context.Background(), net.DomainAddress(tempSocket), 0, &internet.MemoryStreamConfig{
+		ProtocolName: "splithttp",
+		ProtocolSettings: &Config{
+			Path: "/sh",
+		},
+	}, func(conn stat.Connection) {
+		go func(c stat.Connection) {
+			defer c.Close()
+
+			var b [1024]byte
+			c.SetReadDeadline(time.Now().Add(2 * time.Second))
+			_, err := c.Read(b[:])
+			if err != nil {
+				return
+			}
+
+			common.Must2(c.Write([]byte("Response")))
+		}(conn)
+	})
+	common.Must(err)
+	ctx := context.Background()
+	streamSettings := &internet.MemoryStreamConfig{
+		ProtocolName: "splithttp",
+		ProtocolSettings: &Config{
+			Host: "example.com",
+			Path: "sh",
+		},
+	}
+	conn, err := Dial(ctx, net.UnixDestination(net.DomainAddress(tempSocket)), streamSettings)
+
+	common.Must(err)
+	_, err = conn.Write([]byte("Test connection 1"))
+	common.Must(err)
+
+	var b [1024]byte
+	fmt.Println("test2")
+	n, _ := conn.Read(b[:])
+	fmt.Println("string is", n)
+	if string(b[:n]) != "Response" {
+		t.Error("response: ", string(b[:n]))
+	}
+
+	common.Must(conn.Close())
+	conn, err = Dial(ctx, net.UnixDestination(net.DomainAddress(tempSocket)), streamSettings)
+
+	common.Must(err)
+	_, err = conn.Write([]byte("Test connection 2"))
+	common.Must(err)
+	n, _ = conn.Read(b[:])
+	common.Must(err)
+	if string(b[:n]) != "Response" {
+		t.Error("response: ", string(b[:n]))
+	}
+	common.Must(conn.Close())
+
+	common.Must(listen.Close())
+}