Change dart:io to use Future for one-shot operations.

samples/total/server/TotalRunner.dart

 #!/usr/bin/env 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.
 
 #library("total:runner");
 
 #import('dart:io');
 
 typedef void ExitCallback(int status, String exitString);
@@ skipping 34 matching lines @@
     var foundExec;
     for (String dartExec in DART_EXECS) {
       var file = new File(dartExec);
       if (file.existsSync()) {
         foundExec = dartExec;
       }
     }
     if (foundExec == null) {
       print("No executable found on DART_EXECS:\n" + DART_EXECS);
       exitCallback(1, this);
-      return;      
+      return;
     }
-    Process dart = new Process.start(foundExec, [_serverMain]);
+    Process dart = Process.start(foundExec, [_serverMain]);
 
     dart.onExit = (int status) {
       dart.close();
       exitCallback(status, this);
     };
 
     dart.stdout.onData = () => readMore(dart.stdout, new StringBuffer());
     dart.stderr.onData = () => readMore(dart.stderr, new StringBuffer());
   }
 
@@ skipping 10 matching lines @@
         } else {
           String line = readSoFar.toString();
           readSoFar.clear();
           if (line.length != 0) {
             print(line);
           }
         }
       });
   }
 }