etcdserver/api/rafthttp/util.go
func NewRoundTripper(tlsInfo transport.TLSInfo, dialTimeout time.Duration) (http.RoundTripper, error) {
	// It uses timeout transport to pair with remote timeout listeners.
	// It sets no read/write timeout, because message in requests may
	// take long time to write out before reading out the response.
	return transport.NewTimeoutTransport(tlsInfo, dialTimeout, 0, 0)
}
func NewRoundTripper(tlsInfo transport.TLSInfo, dialTimeout time.Duration) (http.RoundTripper, error) {
	// It uses timeout transport to pair with remote timeout listeners.
	// It sets no read/write timeout, because message in requests may
	// take long time to write out before reading out the response.
	return transport.NewTimeoutTransport(tlsInfo, dialTimeout, 0, 0)
}
// NewRoundTripper returns a roundTripper used to send requests
// to rafthttp listener of remote peers.