title: Read file as a buffer within an Expo application
body: <p>Specific problem is that the <a href="https://docs.expo.io/versions/latest/sdk/filesystem.html" rel="noreferrer">Expo filesystem</a> can only read a file as a string, but my desired usage (more below) is to read the file as a buffer. I'm hunting around the alternative filesystem libraries, but I'm not finding a clear solution.</p>
  
  <p>At this level, my question is just simply: In an Expo app (so, react native), how can I read a file as a buffer?</p>
  
  <p>The larger context is that I'm trying to do some photo processing with the JSFeat library. This library expects <code>Uint8ClampedArray</code> objects, which can be created from JPG files by the <a href="https://github.com/notmasteryet/jpgjs" rel="noreferrer">JPEG-JS</a> library, and the Expo camera library automatically saves the photo to a JPG file.</p>