code: public static ReadableByteChannel newChannel(final InputStream in) {
          checkNotNull(in, "in");
  
          if (in instanceof FileInputStream &&
              FileInputStream.class.equals(in.getClass())) {
              return ((FileInputStream)in).getChannel();
          }
  
          return new ReadableByteChannelImpl(in);
      }
docs: Constructs a channel that reads bytes from the given stream.
  
  <p> The resulting channel will not be buffered; it will simply redirect
  its I/O operations to the given stream.  Closing the channel will in
  turn cause the stream to be closed.  </p>
  
  @param  in
  The stream from which bytes are to be read
  
  @return  A new readable byte channel