add readme

README.md

@@ -0,0 +1,55 @@
+#Streams#
+
+[![Build Status](https://travis-ci.org/icewind1991/Streams.svg?branch=master)](https://travis-ci.org/icewind1991/Streams)
+[![Coverage Status](https://img.shields.io/coveralls/icewind1991/Streams.svg)](https://coveralls.io/r/icewind1991/Streams?branch=master)
+
+Generic stream wrappers for php.
+
+##CallBackWrapper##
+
+A `CallBackWrapper` can be used to register callbacks on read, write and closing of the stream,
+it wraps an existing stream and can thus be used for any stream in php
+
+The callbacks are passed in the stream context along with the source stream
+and can be any valid [php callable](http://php.net/manual/en/language.types.callable.php)
+
+###Example###
+```php
+<?php
+
+use \Icewind\Streams\CallBackWrapper;
+
+require('vendor/autoload.php');
+
+stream_wrapper_register('callback', '\Icewind\Streams\CallbackWrapper');
+
+// get an existing stream to wrap
+$source = fopen('php://temp', 'r+');
+
+$context = stream_context_create(array(
+	'callback' => array(
+		'source' => $source,
+		'read' => function ($count) {
+				echo "read " . $count . "bytes\n";
+			},
+		'write' => function ($data) {
+				echo "wrote '" . $data . "'\n";
+			},
+		'close' => function () {
+				echo "stream closed\n";
+			}
+	)
+));
+$stream = fopen('callback://', 'r+', false, $context);
+
+fwrite($stream, 'some dummy data');
+
+rewind($stream);
+fread($stream, 5);
+
+fclose($stream);
+```
+
+Note: due to php's internal stream buffering the `$count` passed to the read callback
+will be equal to php's internal buffer size (8192 on default) an not the number of bytes
+requested by `fopen()`