⚡ Fix the RandString method cause the lag

pkg/internal/services/random_id.go

@@ -2,30 +2,14 @@ package services
 
 import (
 	"math/rand"
-	"strings"
 )
 
-const letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
-const (
-	letterIdxBits = 6
-	letterIdxMask = 1<<letterIdxBits - 1
-	letterIdxMax  = 63 / letterIdxBits
-)
+var letters = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
 
 func RandString(length int) string {
-	builder := strings.Builder{}
-	builder.Grow(length)
-	for idx, cache, remain := length-1, rand.Int63(), letterIdxMax; idx >= 0; {
-		if remain == 0 {
-			cache, remain = rand.Int63(), letterIdxMax
-		}
-		if idx := int(cache & letterIdxMask); idx < len(letterBytes) {
-			builder.WriteByte(letterBytes[idx])
-			idx--
-		}
-		cache >>= letterIdxBits
-		remain--
+	builder := make([]rune, length)
+	for i := range builder {
+		builder[i] = letters[rand.Intn(len(letters))]
 	}
-
-	return builder.String()
+	return string(builder)
 }