diff --git a/lib/parse_http.js b/lib/parse_http.js
index 85e3519..c6b67d7 100644
--- a/lib/parse_http.js
+++ b/lib/parse_http.js
@@ -1,16 +1,16 @@
+module.exports = parseHttpRequest
+
 var common = require('./common')
 
 var REMOVE_IPV6_RE = /^::ffff:/
 
-module.exports = parseHttpRequest
-
 function parseHttpRequest (req, options) {
   var s = req.url.split('?')
   var params = common.querystringParse(s[1])
 
   if (s[0] === '/announce') {
     params.action = common.ACTIONS.ANNOUNCE
-    
+
     params.peer_id = typeof params.peer_id === 'string' && common.binaryToUtf8(params.peer_id)
     params.port = Number(params.port)
 
diff --git a/lib/parse_udp.js b/lib/parse_udp.js
index 7e5ccdf..2122d96 100644
--- a/lib/parse_udp.js
+++ b/lib/parse_udp.js
@@ -1,10 +1,9 @@
+module.exports = parseUdpRequest
+
 var bufferEqual = require('buffer-equal')
 var ipLib = require('ip')
 var common = require('./common')
 
-
-module.exports = parseUdpRequest
-
 function parseUdpRequest (msg, rinfo) {
   if (msg.length < 16) {
     throw new Error('received packet is too short')
@@ -20,7 +19,7 @@ function parseUdpRequest (msg, rinfo) {
     transactionId: msg.readUInt32BE(12)
   }
 
-  // TODO: randomize:
+  // TODO: randomize
   if (!bufferEqual(params.connectionId, common.CONNECTION_ID)) {
     throw new Error('received packet with invalid connection id')
   }
diff --git a/lib/swarm.js b/lib/swarm.js
index 40e4577..b7c2baa 100644
--- a/lib/swarm.js
+++ b/lib/swarm.js
@@ -1,7 +1,7 @@
-var debug = require('debug')('bittorrent-tracker')
-
 module.exports = Swarm
 
+var debug = require('debug')('bittorrent-tracker')
+
 // Regard this as the default implementation of an interface that you
 // need to support when overriding Server.getSwarm()
 function Swarm (infoHash, server) {
@@ -19,30 +19,27 @@ Swarm.prototype.announce = function (params, cb) {
   if (!params.event || params.event === 'empty') params.event = 'update'
   var fn = '_onAnnounce_' + params.event
   if (self[fn]) {
-    self[fn](params, peer, function (err) {
-      // event processed, prepare response:
+    self[fn](params, peer) // process event
 
-      if (params.left === 0 && peer) peer.complete = true
+    if (params.left === 0 && peer) peer.complete = true
 
-      // send peers
-      var peers = self._getPeers(params.numwant)
-
-      cb(null, {
-        complete: self.complete,
-        incomplete: self.incomplete,
-        peers: peers
-      })
+    cb(null, {
+      complete: self.complete,
+      incomplete: self.incomplete,
+      peers: self._getPeers(params.numwant)
     })
+
   } else {
     cb(new Error('invalid event'))
   }
 }
 
-Swarm.prototype._onAnnounce_started = function (params, peer, cb) {
+Swarm.prototype._onAnnounce_started = function (params, peer) {
   if (peer) {
     debug('unexpected `started` event from peer that is already in swarm')
-    return this._onAnnounce_update() // treat as an update
+    return this._onAnnounce_update(params, peer) // treat as an update
   }
+
   if (params.left === 0) this.complete += 1
   else this.incomplete += 1
   peer = this.peers[params.addr] = {
@@ -51,48 +48,42 @@ Swarm.prototype._onAnnounce_started = function (params, peer, cb) {
     peerId: params.peer_id
   }
   this.emit('start', params.addr)
-
-  cb()
 }
 
-Swarm.prototype._onAnnounce_stopped = function (params, peer, cb) {
+Swarm.prototype._onAnnounce_stopped = function (params, peer) {
   if (!peer) {
     debug('unexpected `stopped` event from peer that is not in swarm')
     return // do nothing
   }
+
   if (peer.complete) this.complete -= 1
   else this.incomplete -= 1
   this.peers[params.addr] = null
   this.emit('stop', params.addr)
-
-  cb()
 }
 
-Swarm.prototype._onAnnounce_completed = function (params, peer, cb) {
+Swarm.prototype._onAnnounce_completed = function (params, peer) {
   if (!peer) {
     debug('unexpected `completed` event from peer that is not in swarm')
-    return start() // treat as a start
+    return this._onAnnounce_started(params, peer) // treat as a start
   }
   if (peer.complete) {
     debug('unexpected `completed` event from peer that is already marked as completed')
     return // do nothing
   }
+
   this.complete += 1
   this.incomplete -= 1
   peer.complete = true
   this.emit('complete', params.addr)
-
-  cb()
 }
 
-Swarm.prototype._onAnnounce_update = function (params, peer, cb) {
+Swarm.prototype._onAnnounce_update = function (params, peer) {
   if (!peer) {
     debug('unexpected `update` event from peer that is not in swarm')
-    return start() // treat as a start
+    return this._onAnnounce_started(params, peer) // treat as a start
   }
   this.emit('update', params.addr)
-
-  cb()
 }
 
 Swarm.prototype._getPeers = function (numwant) {
@@ -110,7 +101,7 @@ Swarm.prototype._getPeers = function (numwant) {
   return peers
 }
 
-Swarm.prototype.scrape = function (infoHash, params, cb) {
+Swarm.prototype.scrape = function (params, cb) {
   cb(null, {
     complete: this.complete,
     incomplete: this.incomplete
diff --git a/server.js b/server.js
index ed1a229..af1dd49 100644
--- a/server.js
+++ b/server.js
@@ -147,7 +147,7 @@ Server.prototype._onHttpRequest = function (req, res) {
     // even though it's an error for the client, it's just a warning for the server.
     // don't crash the server because a client sent bad data :)
     self.emit('warning', error)
-    
+
     return
   }
 
@@ -185,7 +185,7 @@ Server.prototype._onUdpRequest = function (msg, rinfo) {
         'failure reason': err.message
       }
     }
-    
+
     var socket = dgram.createSocket('udp4')
     response.transactionId = params.transactionId
     response.connectionId = params.connectionId
@@ -199,7 +199,6 @@ Server.prototype._onUdpRequest = function (msg, rinfo) {
 }
 
 Server.prototype._onRequest = function (params, cb) {
-  var response
   if (params && params.action === common.ACTIONS.CONNECT) {
     cb(null, { action: common.ACTIONS.CONNECT })
   } else if (params && params.action === common.ACTIONS.ANNOUNCE) {
@@ -230,7 +229,7 @@ Server.prototype._onAnnounce = function (params, cb) {
 
 Server.prototype._onScrape = function (params, cb) {
   var self = this
-  
+
   if (typeof params.info_hash === 'string') {
     params.info_hash = [ params.info_hash ]
   } else if (params.info_hash == null) {
@@ -238,13 +237,13 @@ Server.prototype._onScrape = function (params, cb) {
     // TODO: make this configurable!
     params.info_hash = Object.keys(self.torrents)
   }
-  
+
   if (!Array.isArray(params.info_hash)) {
     var err = new Error('invalid info_hash')
     self.emit('warning', err)
     return cb(err)
   }
-  
+
   var response = {
     action: common.ACTIONS.SCRAPE,
     files: {},
@@ -256,7 +255,7 @@ Server.prototype._onScrape = function (params, cb) {
   series(params.info_hash.map(function (infoHash) {
     var swarm = self.getSwarm(infoHash)
     return function (cb) {
-      swarm.scrape(infoHash, params, function (err, scrapeInfo) {
+      swarm.scrape(params, function (err, scrapeInfo) {
         cb(err, scrapeInfo && {
           infoHash: infoHash,
           complete: scrapeInfo.complete || 0,