Fix issues found by analyzer.

lib/io/input_stream.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /**
  * Basic input stream which supplies binary data.
  *
  * Input streams are used to read data sequentially from some data
  * source. All input streams are non-blocking. They each have a number
  * of read calls which will always return without any IO related
@@ skipping 42 matching lines @@
    */
   int available();
 
   /**
    * Pipe the content of this input stream directly to the output
    * stream [output]. The default behavior is to close the output when
    * all the data from the input stream have been written. Specifying
    * `false` for the optional argument [close] keeps the output
    * stream open after writing all data from the input stream.
    */
-  void pipe(OutputStream output, [bool close = true]);
+  void pipe(OutputStream output, {bool close: true});
 
   /**
    * 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();
 
@@ skipping 168 matching lines @@
   void set onError(void callback(e));
 }
 
 
 class StreamException implements Exception {
   const StreamException([String this.message = ""]);
   const StreamException.streamClosed() : message = "Stream closed";
   String toString() => "StreamException: $message";
   final String message;
 }