add conn limiter

limiter/traffic/limiter.go

@@ -0,0 +1,30 @@
+package traffic
+
+import (
+	"context"
+
+	limiter "github.com/go-gost/core/limiter/traffic"
+	"golang.org/x/time/rate"
+)
+
+type llimiter struct {
+	limiter *rate.Limiter
+}
+
+func NewLimiter(r int) limiter.Limiter {
+	return &llimiter{
+		limiter: rate.NewLimiter(rate.Limit(r), r),
+	}
+}
+
+func (l *llimiter) Wait(ctx context.Context, n int) int {
+	if l.limiter.Burst() < n {
+		n = l.limiter.Burst()
+	}
+	l.limiter.WaitN(ctx, n)
+	return n
+}
+
+func (l *llimiter) Limit() int {
+	return l.limiter.Burst()
+}