Added README.

README.md

@@ -87,6 +87,7 @@ API
 ---
 
   * <a href="#generate"><code>mqtt#<b>generate()</b></code></a>
+  * <a href="#writeToStream"><code>mqtt#<b>writeToStream()</b></code></a>
   * <a href="#parser"><code>mqtt#<b>parser()</b></code></a>
 
 <a name="generate">
@@ -96,6 +97,36 @@ Generates a `Buffer` containing an MQTT packet.
 The object must be one of the ones specified by the [packets](#packets)
 section. Throws an `Error` if a packet cannot be generated.
 
+<a name="writeToStream">
+### mqtt.writeToStream(object, stream)
+
+Writes the mqtt packet defined by `object` to the given stream.
+The object must be one of the ones specified by the [packets](#packets)
+section. Emits an `Error` on the stream if a packet cannot be generated.
+
+This function is best used with `cork()` in the Streams3 API, as
+follows:
+
+```js
+
+funciton send(packet, stream) {
+  stream.cork()
+  var res = mqtt.writeToStream({
+      cmd: 'publish'
+    , topic: 'test'
+    , payload: buf
+  }, stream);
+  process.nextTick(uncork, stream);
+}
+
+// this should be defined at the top
+// level
+function uncork (stream) {
+  stream.uncork()
+}
+
+```
+
 <a name="parser">
 ### mqtt.parser()