fix(gin): data race warning for gin mode (#1580)

* fix: data race warning (#1180)

* Fix the tests

* refactor: remove unnecessary imports and optimize codebase

- Remove unnecessary import of `flag`

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* test: refactor test assertions for mode settings

- Update test assertions for mode setting in `mode_test.go`

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

---------

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>
Co-authored-by: Bo-Yi Wu <appleboy.tw@gmail.com>

debug.go

@@ -10,6 +10,7 @@ import (
 	"runtime"
 	"strconv"
 	"strings"
+	"sync/atomic"
 )
 
 const ginSupportMinGoVer = 18
@@ -17,7 +18,7 @@ const ginSupportMinGoVer = 18
 // IsDebugging returns true if the framework is running in debug mode.
 // Use SetMode(gin.ReleaseMode) to disable debug mode.
 func IsDebugging() bool {
-	return ginMode == debugCode
+	return atomic.LoadInt32(&ginMode) == debugCode
 }
 
 // DebugPrintRouteFunc indicates debug log output format.