http.go
func (req *Request) SetBodyString(body string) {
	req.RemoveMultipartFormFiles()
	req.closeBodyStream()
	req.bodyBuffer().SetString(body)
}
func (req *Request) SetBodyString(body string) {
	req.RemoveMultipartFormFiles()
	req.closeBodyStream()
	req.bodyBuffer().SetString(body)
}
// SetBodyString sets request body.