http.go
func (resp *Response) SetBodyString(body string) {
	resp.closeBodyStream()
	bodyBuf := resp.bodyBuffer()
	bodyBuf.Reset()
	bodyBuf.WriteString(body)
}
func (resp *Response) SetBodyString(body string) {
	resp.closeBodyStream()
	bodyBuf := resp.bodyBuffer()
	bodyBuf.Reset()
	bodyBuf.WriteString(body)
}
// SetBodyString sets response body.