title: flutter: got error when I add http dependency
body: <p>I'm studying flutter networking in <a href="https://flutter.dev/docs/cookbook/networking/send-data" rel="nofollow noreferrer">flutter docs</a>. I totally follow the guidance but when I add http dependency then click <code>Packages get</code> then I get an error. What's wrong? Thanks for any advice.</p>
  <pre><code>dependencies:
    flutter:
      sdk: flutter
    qrscan: ^0.2.17
    # The following adds the Cupertino Icons font to your application.
    # Use with the CupertinoIcons class for iOS style icons.
    cupertino_icons: ^0.1.3
    http: ^0.12.2  // http dependency I added
  </code></pre>
  <p>the error info is below</p>
  <pre><code>Running &quot;flutter pub get&quot; in myProject...                        
  Unexpected character (at character 1)
  
  &lt;html&gt;
  
  ^
  
  dart:convert                                       jsonDecode
  
  package:pub/src/source/hosted.dart 190:17          BoundHostedSource._fetchVersions
  
  ===== asynchronous gap ===========================
  
  dart:async                                         _CustomZone.runUnary
  
  package:pub/src/rate_limited_scheduler.dart 82:30  RateLimitedScheduler._processNextTask.runJob
  
  package:pub/src/rate_limited_scheduler.dart 85:30  RateLimitedScheduler._processNextTask
  
  dart:async                                         new Future.sync
  
  package:pool/pool.dart 126:18                      Pool.withResource.&lt;fn&gt;
  
  This is an unexpected error. Please run
  
  
  
      pub --trace '--verbosity=warning' get --no-precompile
  
  
  
  and include the logs in an issue on https://github.com/dart-lang/pub/issues/new
  pub get failed (65; and include the logs in an issue on https://github.com/dart-lang/pub/issues/new)
  Process finished with exit code 65
  </code></pre>