Add close to input stream and cleanup socket and streams

runtime/bin/input_stream.dart

Index: runtime/bin/input_stream.dart
diff --git a/runtime/bin/input_stream.dart b/runtime/bin/input_stream.dart
index e6e66264a76627657ddbf8113596a5d4bef69f51..a4bc010d9bcb3121bb87029710f3593ce683f89b 100644
--- a/runtime/bin/input_stream.dart
+++ b/runtime/bin/input_stream.dart
@@ -67,6 +67,15 @@ interface InputStream {
   void pipe(OutputStream output, [bool close]);
 
   /**
+   * Close the underlying communication channel to avoid getting any
+   * more data. In normal situations, where all data is read from the
+   * stream until the close handler is called, calling [close] is not
+   * required. When [close] is used the close handler will still be
+   * called.
+   */
+  void close();
+
+  /**
    * Returns whether the stream is closed. There will be no more data
    * to read.
    */