Revert until Windows crash is debugged.

pkg/scheduled_test/lib/src/utils.dart

 // Copyright (c) 2013, 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 utils;
 
 import 'dart:async';
 
 import 'package:stack_trace/stack_trace.dart';
 
@@ skipping 76 matching lines @@
         controller.add,
         onError: (error) => controller.addError(error),
         onDone: controller.close);
   }).catchError((e) {
     controller.addError(e);
     controller.close();
   });
   return controller.stream;
 }
 
-/// Returns the first element of a [StreamIterator].
-///
-/// If the [StreamIterator] has no elements, the result is a state error.
-Future<String> streamIteratorFirst(StreamIterator<String> streamIterator) {
-  StackTrace stackTrace = new Trace.current();
-  return streamIterator.moveNext().then((hasNext) {
-    if (hasNext) {
-      return streamIterator.current;
-    } else {
-      return new Future.error(new StateError("No elements"), stackTrace);
-    }
-  });
-}
+// TODO(nweiz): remove this when issue 7964 is fixed.
+/// Returns a [Future] that will complete to the first element of [stream].
+/// Unlike [Stream.first], this is safe to use with single-subscription streams.
+Future streamFirst(Stream stream) {
+  var stackTrace;
+  try {
+    throw '';
+  } catch (_, thrownStackTrace) {
+    stackTrace = thrownStackTrace;
+  }
 
-/// Collects all remaining lines from a [StreamIterator] of lines.
-///
-/// Returns the concatenation of the collected lines joined by newlines.
-Future<String> concatRest(StreamIterator<String> streamIterator) {
-  var completer = new Completer<String>();
-  var buffer = new StringBuffer();
-  void collectAll() {
-    streamIterator.moveNext().then((hasNext) {
-      if (hasNext) {
-        if (!buffer.isEmpty) buffer.write('\n');
-        buffer.write(streamIterator.current);
-        collectAll();
-      } else {
-        completer.complete(buffer.toString());
-      }
-    }, onError: completer.completeError);
-  }
-  collectAll();
+  var completer = new Completer();
+  var subscription;
+  subscription = stream.listen((value) {
+    subscription.cancel();
+    completer.complete(value);
+  }, onError: (e) {
+    completer.completeError(e);
+  }, onDone: () {
+    completer.completeError(new StateError("No elements"), stackTrace);
+  }, cancelOnError: true);
   return completer.future;
 }
 
 /// A function that can be called to cancel a [Stream] and send a done message.
 typedef void StreamCanceller();
 
 // TODO(nweiz): use a StreamSubscription when issue 9026 is fixed.
 /// Returns a wrapped version of [stream] along with a function that will cancel
 /// the wrapped stream. Unlike [StreamSubscription], this canceller will send a
 /// "done" message to the wrapped stream.
@@ skipping 63 matching lines @@
 }
 
 /// Returns a string representation of [trace] that has the core and test frames
 /// folded together.
 String terseTraceString(StackTrace trace) {
   return new Trace.from(trace).terse.foldFrames((frame) {
     return frame.package == 'scheduled_test' || frame.package == 'unittest' ||
         frame.isCore;
   }).toString().trim();
 }