title: FileUtils.copyFile() VS FileChannel.transferTo()
body: <p>As I found, underlying OS call for the <code>copyToFile()</code> is <code>Libcore.os.read(fd, bytes, byteOffset, byteCount)</code>, while <code>transferTo()</code> is based on memory mapped file:</p>
  
  <pre><code>MemoryBlock.mmap(fd, alignment, size + offset, mapMode);
  ...
  buffer = map(MapMode.READ_ONLY, position, count);
  return target.write(buffer);
  </code></pre>
  
  <p>Q1: Am I right or wrong in my findings?<br>
  Q2: Is there any reason to use <code>FileUtils.copyFile()</code> as <code>FileChannel.transferTo()</code> seems should be more efficient?</p>
  
  <p>Thanks</p>