refactor and organize code

internal/net/gphttp/middleware/modify_response.go

@@ -0,0 +1,20 @@
+package middleware
+
+import (
+	"net/http"
+)
+
+type modifyResponse struct {
+	ModifyRequestOpts
+	Tracer
+}
+
+var ModifyResponse = NewMiddleware[modifyResponse]()
+
+// modifyResponse implements ResponseModifier.
+func (mr *modifyResponse) modifyResponse(resp *http.Response) error {
+	mr.AddTraceResponse("before modify response", resp)
+	mr.modifyHeaders(resp.Request, resp, resp.Header)
+	mr.AddTraceResponse("after modify response", resp)
+	return nil
+}