/// 客户端启动中继连接
/// 1、swarm.dial("/ip4/xxx/peer/peer-relay-server/circuit/remote-addr")
/// 2、Transport 收到中继请求。 向Behavior发送 DialOpts
/// 3、Behavior 处理 DialOpts,向 PeerRelayServer 发送OutboundRequest
/// 4、OutboundRequest 协商成功后,通知Transport 建立连接(Substream -> Connection)
pub use Behavior;
use cratetransport;