use package level defined contextKey as context key

rest/internal/log.go

@@ -10,7 +10,7 @@ import (
 	"github.com/tal-tech/go-zero/rest/httpx"
 )
 
-const LogContext = "request_logs"
+var LogContext = contextKey("request_logs")
 
 type LogCollector struct {
 	Messages []string
@@ -82,3 +82,9 @@ func formatf(r *http.Request, format string, v ...interface{}) string {
 func formatWithReq(r *http.Request, v string) string {
 	return fmt.Sprintf("(%s - %s) %s", r.RequestURI, httpx.GetRemoteAddr(r), v)
 }
+
+type contextKey string
+
+func (c contextKey) String() string {
+	return "rest/internal context key " + string(c)
+}