http.go
func (req *Request) CopyTo(dst *Request) {
	req.copyToSkipBody(dst)
	if req.body != nil {
		dst.bodyBuffer().Set(req.body.B)
	} else if dst.body != nil {
		dst.body.Reset()
	}
}
func (req *Request) CopyTo(dst *Request) {
	req.copyToSkipBody(dst)
	if req.body != nil {
		dst.bodyBuffer().Set(req.body.B)
	} else if dst.body != nil {
		dst.body.Reset()
	}
}
// CopyTo copies req contents to dst except of body stream.