Add Streaming interface

Author: thekid

src/main/php/com/amazon/aws/lambda/Streaming.class.php

@@ -0,0 +1,15 @@
+<?php namespace com\amazon\aws\lambda;
+
+interface Streaming {
+
+  /**
+   * Invoke this lambda with the given event and context, streaming the
+   * response using the given stream.
+   *
+   * @param  var $event
+   * @param  com.amazon.aws.lambda.Stream $stream
+   * @param  com.amazon.aws.lambda.Context $context
+   * @return void
+   */
+  public function handle($event, $stream, $context);
+}