feat(transport): use parallel limited dialer (#195)

* feat(transport): use parallel limited dialer

package.json

@@ -87,4 +87,4 @@
     "greenkeeper[bot] <greenkeeper[bot]@users.noreply.github.com>",
     "ᴠɪᴄᴛᴏʀ ʙᴊᴇʟᴋʜᴏʟᴍ <[email protected]>"
   ]
-}
+}

src/transport.js

@@ -1,6 +1,8 @@
 'use strict'
 
 const parallel = require('async/parallel')
+const queue = require('async/queue')
+const timeout = require('async/timeout')
 const once = require('once')
 const debug = require('debug')
 const log = debug('libp2p:swarm:transport')
@@ -14,6 +16,12 @@ const defaultPerPeerRateLimit = 8
 // the amount of time a single dial has to succeed
 const dialTimeout = 10 * 1000
 
+// number of concurrent outbound dials to make per peer, same as go-libp2p-swarm
+const defaultPerPeerRateLimit = 8
+
+// the amount of time a single dial has to succeed
+const dialTimeout = 10 * 1000
+
 module.exports = function (swarm) {
   const dialer = new LimitDialer(defaultPerPeerRateLimit, dialTimeout)
 
@@ -130,4 +138,13 @@ function dialables (tp, multiaddrs) {
   return tp.filter(multiaddrs)
 }
 
+function dialWithTimeout (transport, multiaddr, maxTimeout, callback) {
+  timeout((cb) => {
+    const conn = transport.dial(multiaddr, (err) => {
+      log('dialed')
+      cb(err, conn)
+    })
+  }, maxTimeout)(callback)
+}
+
 function noop () {}