title: Hot reload stuck after first try
body: <p>I am using vscode to developing flutter application , I don't know what is going on ! When I save project and try to hot reload just one time it's work and notification of hot reloading(<code>Performing hot reload</code>) remain at bottom of vscode and next hot reloading not works.</p>
  <p><a href="https://i.stack.imgur.com/iVESL.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/iVESL.png" alt="enter image description here" /></a></p>
  <p>Vscode not throw any error or something to catch a problem so I run application with <code>run</code> command and after hot reload, this is it's result :</p>
  <pre><code>Flutter run key commands.
  r Hot reload. 
  R Hot restart.
  h Repeat this help message.
  d Detach (terminate &quot;flutter run&quot; but leave application running).
  c Clear the screen
  q Quit (terminate the application on the device).
  An Observatory debugger and profiler on sdk gphone x86 arm is available at: http://127.0.0.1:40989/zVisdoiRRE8=/
  
  Flutter DevTools, a Flutter debugger and profiler, on sdk gphone x86 arm is available at: http://127.0.0.1:9101?uri=http%3A%2F%2F127.0.0.1%3A40989%2FzVisdoiRRE8%3D%2F
  
  Running with unsound null safety
  For more information see https://dart.dev/null-safety/unsound-null-safety
  
  Performing hot reload...  
  </code></pre>
  <p>Now when I press r , hot reload not working .</p>
  <p>I am using fvm and This is my sdk version :</p>
  <pre><code>$ flutter doctor -v
  [✓] Flutter (Channel unknown, 2.0.6, on Linux, locale en_US.UTF-8)
      • Flutter version 2.0.6 at /home/alt/fvm/versions/2.0.6
      • Framework revision 1d9032c7e1 (5 weeks ago), 2021-04-29 17:37:58 -0700
      • Engine revision 05e680e202
      • Dart version 2.12.3
  
  [✓] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
      • Android SDK at /mnt/SSDP/Sdk/android/
      • Platform android-S, build-tools 30.0.3
      • ANDROID_HOME = /mnt/SSDP/Sdk/android
      • ANDROID_SDK_ROOT = /mnt/SSDP/Sdk/android/
      • Java binary at: /mnt/SSDP/android-studio/jre/bin/java
      • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)
      • All Android licenses accepted.
  
  [✓] Chrome - develop for the web
      • Chrome at google-chrome
  
  [✓] Android Studio
      • Android Studio at /mnt/SSDP/android-studio/
      • Flutter plugin can be installed from:
         https://plugins.jetbrains.com/plugin/9212-flutter
      • Dart plugin can be installed from:
         https://plugins.jetbrains.com/plugin/6351-dart
      • android-studio-dir = /mnt/SSDP/android-studio/
      • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)
  
  [✓] VS Code (version 1.56.2)
      • VS Code at /usr/share/code
      • Flutter extension version 3.23.0
  
  [✓] Connected device (2 available)
      • Android SDK built for x86 (mobile) • emulator-5554 • android-x86    • Android 10 (API 29)
        (emulator)
      • Chrome (web)                       • chrome        • web-javascript • Google Chrome
        91.0.4472.77
  
  • No issues found!
  </code></pre>
  <ul>
  <li>I faced this problem with Android studio too.</li>
  </ul>