refactor(misc): enhance performance on bytes pool, entrypoint, access log and route context handling

- Introduced benchmark tests for Entrypoint and ReverseProxy to evaluate performance.
- Updated Entrypoint's ServeHTTP method to improve route context management.
- Added new test file for entrypoint benchmarks and refined existing tests for route handling.

internal/route/routes/context.go

@@ -2,18 +2,42 @@ package routes
 
 import (
 	"context"
+	"crypto/tls"
+	"fmt"
+	"io"
+	"mime/multipart"
 	"net/http"
 	"net/url"
+	"reflect"
+	"unsafe"
 
 	"github.com/yusing/go-proxy/internal/types"
 )
 
-type RouteContext struct{}
+type RouteContextKey struct{}
 
-var routeContextKey = RouteContext{}
+type RouteContext struct {
+	context.Context
+	Route types.HTTPRoute
+}
+
+var routeContextKey = RouteContextKey{}
+
+func (r *RouteContext) Value(key any) any {
+	if key == routeContextKey {
+		return r.Route
+	}
+	return r.Context.Value(key)
+}
 
 func WithRouteContext(r *http.Request, route types.HTTPRoute) *http.Request {
-	return r.WithContext(context.WithValue(r.Context(), routeContextKey, route))
+	// we don't want to copy the request object every fucking requests
+	// return r.WithContext(context.WithValue(r.Context(), routeContextKey, route))
+	(*requestInternal)(unsafe.Pointer(r)).ctx = &RouteContext{
+		Context: r.Context(),
+		Route:   route,
+	}
+	return r
 }
 
 func TryGetRoute(r *http.Request) types.HTTPRoute {
@@ -74,3 +98,44 @@ func TryGetUpstreamURL(r *http.Request) string {
 	}
 	return ""
 }
+
+type requestInternal struct {
+	Method           string
+	URL              *url.URL
+	Proto            string
+	ProtoMajor       int
+	ProtoMinor       int
+	Header           http.Header
+	Body             io.ReadCloser
+	GetBody          func() (io.ReadCloser, error)
+	ContentLength    int64
+	TransferEncoding []string
+	Close            bool
+	Host             string
+	Form             url.Values
+	PostForm         url.Values
+	MultipartForm    *multipart.Form
+	Trailer          http.Header
+	RemoteAddr       string
+	RequestURI       string
+	TLS              *tls.ConnectionState
+	Cancel           <-chan struct{}
+	Response         *http.Response
+	Pattern          string
+	ctx              context.Context
+}
+
+func init() {
+	// make sure ctx has the same offset as http.Request
+	f, ok := reflect.TypeFor[requestInternal]().FieldByName("ctx")
+	if !ok {
+		panic("ctx field not found")
+	}
+	f2, ok := reflect.TypeFor[http.Request]().FieldByName("ctx")
+	if !ok {
+		panic("ctx field not found")
+	}
+	if f.Offset != f2.Offset {
+		panic(fmt.Sprintf("ctx has different offset than http.Request: %d != %d", f.Offset, f2.Offset))
+	}
+}