@Override
  public int write(ByteBuffer src) throws IOException {
    return channel.write(src);
  }
A thin wrapper around a {@link FileChannel} that exists only to implement {@link
SeekableByteChannel} but NOT extend {@link FileChannel}.

@author Colin Decker
jimfs/src/main/java/com/google/common/jimfs/DowngradedSeekableByteChannel.java