code: public static AsyncInputStream channelToInputStream(final AsynchronousByteChannel asynchronousByteChannel) {
          notNull("asynchronousByteChannel", asynchronousByteChannel);
          return new AsyncInputStream() {
              @Override
              public void read(final ByteBuffer dst, final SingleResultCallback<Integer> callback) {
                  asynchronousByteChannel.read(dst, null, new CompletionHandler<Integer, Object>() {
                      @Override
                      public void completed(final Integer result, final Object attachment) {
                          callback.onResult(result, null);
                      }
  
                      @Override
                      public void failed(final Throwable exc, final Object attachment) {
                          callback.onResult(null, exc);
                      }
                  });
              }
  
              @Override
              public void skip(final long bytesToSkip, final SingleResultCallback<Long> callback) {
                  notNull("callback", callback);
                  callback.onResult(0L, null);
              }
  
              @Override
              public void close(final SingleResultCallback<Void> callback) {
                  try {
                      asynchronousByteChannel.close();
                      callback.onResult(null, null);
                  } catch (Exception e) {
                      callback.onResult(null, e);
                  }
              }
          };
      }
docs: Converts a {@link AsynchronousByteChannel} into a {@link AsyncInputStream}
  
  @param asynchronousByteChannel the AsynchronousByteChannel
  @return the AsyncInputStream