small improve

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

router/context.go

@@ -0,0 +1,34 @@
+package router
+
+import (
+	"context"
+)
+
+type routerKey struct{}
+
+// FromContext get router from context
+func FromContext(ctx context.Context) (Router, bool) {
+	if ctx == nil {
+		return nil, false
+	}
+	c, ok := ctx.Value(routerKey{}).(Router)
+	return c, ok
+}
+
+// NewContext put router in context
+func NewContext(ctx context.Context, c Router) context.Context {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	return context.WithValue(ctx, routerKey{}, c)
+}
+
+// SetOption returns a function to setup a context with given value
+func SetOption(k, v interface{}) Option {
+	return func(o *Options) {
+		if o.Context == nil {
+			o.Context = context.Background()
+		}
+		o.Context = context.WithValue(o.Context, k, v)
+	}
+}

util/jitter/random.go

@@ -13,3 +13,8 @@ func Random(d time.Duration) time.Duration {
 	v := rng.Float64() * float64(d.Nanoseconds())
 	return time.Duration(v)
 }
+
+func RandomInterval(min, max time.Duration) time.Duration {
+	var rng rand.Rand
+	return time.Duration(rng.Int63n(max.Nanoseconds()-min.Nanoseconds())+min.Nanoseconds()) * time.Nanosecond
+}