Add basic clash api

experimental/clashapi/ctxkeys.go

@@ -0,0 +1,14 @@
+package clashapi
+
+var (
+	CtxKeyProxyName    = contextKey("proxy name")
+	CtxKeyProviderName = contextKey("provider name")
+	CtxKeyProxy        = contextKey("proxy")
+	CtxKeyProvider     = contextKey("provider")
+)
+
+type contextKey string
+
+func (c contextKey) String() string {
+	return "clash context key " + string(c)
+}