Results 2 issues of Huanghy

panic: runtime error: invalid memory address or nil pointer dereference [signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x57b364] goroutine 22 [running]: github.com/json-iterator/go.(*Stream).WriteStringWithHTMLEscaped(0xc4202fec60, 0x0, 0x36) /home/gitlab-runner/sy_go/src/github.com/json-iterator/go/feature_stream_string.go:235 +0x94 github.com/json-iterator/go.(*htmlEscapedStringEncoder).Encode(0x16d4000, 0xc4210e4ea8, 0xc4202fec60) /home/gitlab-runner/sy_go/src/github.com/json-iterator/go/feature_config.go:182 +0x41...

![image](https://user-images.githubusercontent.com/10106550/183853866-ee56aaa3-0b5d-4b30-b9ca-af01491140b7.png) NackBackoffPolicy.Next return int64 type before, but it used as time.Durtion. ![image](https://user-images.githubusercontent.com/10106550/183854274-8405b920-a64a-4324-b969-5c1ee878306a.png)