feat: implement http support

Signed-off-by: Kairee Wu <kaireewu@gmail.com>

client_test.go

@@ -2,6 +2,8 @@ package krpc
 
 import (
 	"net"
+	"os"
+	"runtime"
 	"strings"
 	"testing"
 	"time"
@@ -36,5 +38,24 @@ func TestClient_dialTimeout(t *testing.T) {
 
 		})
 	}
-
+}
+
+func TestXDial(t *testing.T) {
+	if runtime.GOOS == "linux" {
+		ch := make(chan struct{})
+		addr := "/tmp/krpc.sock"
+
+		go func() {
+			_ = os.Remove(addr)
+			l, err := net.Listen("unix", addr)
+			if err != nil {
+				t.Fatal("failed to listen unix socket")
+			}
+			ch <- struct{}{}
+			Accept(l)
+		}()
+		<-ch
+		_, err := XDial("unix://"+addr)
+		_assert(err == nil, "failed to connect unix socket")
+	}
 }