Feat: core.ToContext(ctx, v) for ctx initialization (#852)

context.go

@@ -27,3 +27,19 @@ func MustFromContext(ctx context.Context) *Instance {
 	}
 	return v
 }
+
+// ToContext returns ctx from the given context, or creates an Instance if the context doesn't find that.
+func ToContext(ctx context.Context, v *Instance) context.Context {
+	if FromContext(ctx) != v {
+		ctx = context.WithValue(ctx, v2rayKey, v)
+	}
+	return ctx
+}
+
+// MustToContext returns ctx from the given context, or panics if not found that.
+func MustToContext(ctx context.Context, v *Instance) context.Context {
+	if c := ToContext(ctx, v); c != ctx {
+		panic("V is not in context.")
+	}
+	return ctx
+}