rpc/client: add minimalistic websocket client

pkg/rpc/client/wsclient_test.go

@@ -0,0 +1,16 @@
+package client
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestWSClientClose(t *testing.T) {
+	srv := initTestServer(t, "")
+	defer srv.Close()
+	wsc, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), Options{})
+	require.NoError(t, err)
+	wsc.Close()
+}