vendor: add github.com/xtaci/smux

vendor/github.com/xtaci/smux/README.md

@@ -0,0 +1,99 @@
+<img src="smux.png" alt="smux" height="35px" />
+
+[![GoDoc][1]][2] [![MIT licensed][3]][4] [![Build Status][5]][6] [![Go Report Card][7]][8] [![Coverage Statusd][9]][10]
+
+<img src="mux.jpg" alt="smux" height="120px" /> 
+
+[1]: https://godoc.org/github.com/xtaci/smux?status.svg
+[2]: https://godoc.org/github.com/xtaci/smux
+[3]: https://img.shields.io/badge/license-MIT-blue.svg
+[4]: LICENSE
+[5]: https://travis-ci.org/xtaci/smux.svg?branch=master
+[6]: https://travis-ci.org/xtaci/smux
+[7]: https://goreportcard.com/badge/github.com/xtaci/smux
+[8]: https://goreportcard.com/report/github.com/xtaci/smux
+[9]: https://codecov.io/gh/xtaci/smux/branch/master/graph/badge.svg
+[10]: https://codecov.io/gh/xtaci/smux
+
+## Introduction
+
+Smux ( **S**imple **MU**ltiple**X**ing) is a multiplexing library for Golang. It relies on an underlying connection to provide reliability and ordering, such as TCP or [KCP](https://github.com/xtaci/kcp-go), and provides stream-oriented multiplexing. The original intention of this library is to power the connection management for [kcp-go](https://github.com/xtaci/kcp-go).
+
+## Features
+
+1. Tiny, less than 600 LOC.
+2. ***Token bucket*** controlled receiving, which provides smoother bandwidth graph(see picture below).
+3. Session-wide receive buffer, shared among streams, tightly controlled overall memory usage.
+4. Minimized header(8Bytes), maximized payload. 
+5. Well-tested on millions of devices in [kcptun](https://github.com/xtaci/kcptun).
+
+![smooth bandwidth curve](curve.jpg)
+
+## Documentation
+
+For complete documentation, see the associated [Godoc](https://godoc.org/github.com/xtaci/smux).
+
+## Specification
+
+```
+VERSION(1B) | CMD(1B) | LENGTH(2B) | STREAMID(4B) | DATA(LENGTH)  
+```
+
+## Usage
+
+The API of smux are mostly taken from [yamux](https://github.com/hashicorp/yamux)
+
+```go
+
+func client() {
+    // Get a TCP connection
+    conn, err := net.Dial(...)
+    if err != nil {
+        panic(err)
+    }
+
+    // Setup client side of smux
+    session, err := smux.Client(conn, nil)
+    if err != nil {
+        panic(err)
+    }
+
+    // Open a new stream
+    stream, err := session.OpenStream()
+    if err != nil {
+        panic(err)
+    }
+
+    // Stream implements io.ReadWriteCloser
+    stream.Write([]byte("ping"))
+}
+
+func server() {
+    // Accept a TCP connection
+    conn, err := listener.Accept()
+    if err != nil {
+        panic(err)
+    }
+
+    // Setup server side of smux
+    session, err := smux.Server(conn, nil)
+    if err != nil {
+        panic(err)
+    }
+
+    // Accept a stream
+    stream, err := session.AcceptStream()
+    if err != nil {
+        panic(err)
+    }
+
+    // Listen for a message
+    buf := make([]byte, 4)
+    stream.Read(buf)
+}
+
+```
+
+## Status
+
+Stable