title: How to append write to google cloud storage file from app engine?
body: <p>This deprecated API supports appending content to google cloud storage file:</p>
  
  <pre><code>FileWriteChannel FileService.openWriteChannel(AppEngineFile file,
                                  boolean lock)
  </code></pre>
  
  <p>But, </p>
  
  <pre><code>GcsOutputChannel GcsService.createOrReplace(GcsFilename filename,
                                 GcsFileOptions options)
  </code></pre>
  
  <p>doesn't seem so.</p>
  
  <p>What is the solution here?</p>