Add callback option

README.md

@@ -814,6 +814,7 @@ default in Linux can be anywhere from 20-120 seconds][linux-timeout]).
 
 - `time` - If `true`, the request-response cycle (including all redirects) is timed at millisecond resolution, and the result provided on the response's `elapsedTime` property.
 - `har` - A [HAR 1.2 Request Object](http://www.softwareishard.com/blog/har-12-spec/#request), will be processed from HAR format into options overwriting matching values *(see the [HAR 1.2 section](#support-for-har-1.2) for details)*
+- `callback` - alternatively pass the request's callback in the options object
 
 The callback argument gets 3 arguments:
 

index.js

@@ -37,7 +37,7 @@ function initParams(uri, options, callback) {
     extend(params, uri)
   }
 
-  params.callback = callback
+  params.callback = callback || params.callback
   return params
 }
 

tests/test-api.js

@@ -0,0 +1,30 @@
+'use strict'
+
+var http = require('http')
+  , request = require('../index')
+  , tape = require('tape')
+  , server
+
+
+tape('setup', function (t) {
+  server = http.createServer()
+  server.on('request', function (req, res) {
+    res.writeHead(202)
+    req.pipe(res)
+  })
+  server.listen(6767, t.end)
+})
+
+tape('callback option', function (t) {
+  request({
+    url: 'http://localhost:6767',
+    callback: function (err, res, body) {
+      t.equal(res.statusCode, 202)
+      t.end()
+    }
+  })
+})
+
+tape('cleanup', function(t) {
+  server.close(t.end)
+})