go-micro transport 通信

　　transport 用于服务之间的通信，自定义了socket接口，封装了Send、Recv、Close接口，可以有HTTP、NATS、RPC等实现，默认使用http

type Message struct {
	Header map[string]string
	Body   []byte
}

type Socket interface {
	Recv(*Message) error
	Send(*Message) error
	Close() error
}

type Client interface {
	Socket
}

type Listener interface {
	Addr() string
	Close() error
	Accept(func(Socket)) error
}

// Transport is an interface which is used for communication between
// services. It uses socket send/recv semantics and had various
// implementations {HTTP, RabbitMQ, NATS, ...}
type Transport interface {
	Init(...Option) error
	Options() Options
	Dial(addr string, opts ...DialOption) (Client, error)
	Listen(addr string, opts ...ListenOption) (Listener, error)
	String() string
}

type Option func(*Options)

type DialOption func(*DialOptions)

type ListenOption func(*ListenOptions)