Add observatory / latestPing balancing strategy

Co-authored-by: Shelikhoo <xiaokangwang@outlook.com>

transport/internet/tagged/tagged.go

@@ -0,0 +1,11 @@
+package tagged
+
+import (
+	"context"
+
+	"github.com/xtls/xray-core/common/net"
+)
+
+type DialFunc func(ctx context.Context, dest net.Destination, tag string) (net.Conn, error)
+
+var Dialer DialFunc

transport/internet/tagged/taggedimpl/errors.generated.go

@@ -0,0 +1,9 @@
+package taggedimpl
+
+import "github.com/xtls/xray-core/common/errors"
+
+type errPathObjHolder struct{}
+
+func newError(values ...interface{}) *errors.Error {
+	return errors.New(values...).WithPathObj(errPathObjHolder{})
+}

transport/internet/tagged/taggedimpl/impl.go

@@ -0,0 +1,46 @@
+package taggedimpl
+
+import (
+	"context"
+	"github.com/xtls/xray-core/common/net/cnc"
+	"github.com/xtls/xray-core/core"
+
+	"github.com/xtls/xray-core/common/net"
+	"github.com/xtls/xray-core/common/session"
+	"github.com/xtls/xray-core/features/routing"
+	"github.com/xtls/xray-core/transport/internet/tagged"
+)
+
+func DialTaggedOutbound(ctx context.Context, dest net.Destination, tag string) (net.Conn, error) {
+	var dispatcher routing.Dispatcher
+	if core.FromContext(ctx) == nil {
+		return nil, newError("Instance context variable is not in context, dial denied. ")
+	}
+	if err := core.RequireFeatures(ctx, func(dispatcherInstance routing.Dispatcher) {
+		dispatcher = dispatcherInstance
+	}); err != nil {
+		return nil, newError("Required Feature dispatcher not resolved").Base(err)
+	}
+
+	content := new(session.Content)
+	content.SkipDNSResolve = true
+
+	ctx = session.ContextWithContent(ctx, content)
+	ctx = session.SetForcedOutboundTagToContext(ctx, tag)
+
+	r, err := dispatcher.Dispatch(ctx, dest)
+	if err != nil {
+		return nil, err
+	}
+	var readerOpt cnc.ConnectionOption
+	if dest.Network == net.Network_TCP {
+		readerOpt = cnc.ConnectionOutputMulti(r.Reader)
+	} else {
+		readerOpt = cnc.ConnectionOutputMultiUDP(r.Reader)
+	}
+	return cnc.NewConnection(cnc.ConnectionInputMulti(r.Writer), readerOpt), nil
+}
+
+func init() {
+	tagged.Dialer = DialTaggedOutbound
+}

transport/internet/tagged/taggedimpl/taggedimpl.go

@@ -0,0 +1,3 @@
+package taggedimpl
+
+//go:generate go run github.com/xtls/xray-core/common/errors/errorgen