final byte[] processedBytes = new byte[bytes.length];
    ByteProcessor<byte[]> processor =
        new ByteProcessor<byte[]>() {
          int pos;

          @Override
          public boolean processBytes(byte[] buf, int off, int len) throws IOException {
            System.arraycopy(buf, off, processedBytes, pos, len);
            pos += len;
            return true;
          }

          @Override

        source.read(
            new ByteProcessor<byte[]>() {
              final ByteArrayOutputStream out = new ByteArrayOutputStream();

              @Override
              public boolean processBytes(byte[] buf, int off, int len) throws IOException {
                out.write(buf, off, len);
                return true;
              }

              @Override
              public byte[] getResult() {

    ByteProcessor<byte[]> processor =
        new ByteProcessor<byte[]>() {
          private final ByteArrayOutputStream out = new ByteArrayOutputStream();

          @Override
          public boolean processBytes(byte[] buffer, int offset, int length) throws IOException {
            if (length >= 0) {
              out.write(buffer, offset, length);
            }
            return true;
          }

    final byte[] processedBytes = new byte[bytes.length];
    ByteProcessor<byte[]> processor =
        new ByteProcessor<byte[]>() {
          int pos;

          @Override
          public boolean processBytes(byte[] buf, int off, int len) throws IOException {
            System.arraycopy(buf, off, processedBytes, pos, len);
            pos += len;
            return true;
          }

          @Override

    ByteProcessor<byte[]> processor =
        new ByteProcessor<byte[]>() {
          private final ByteArrayOutputStream out = new ByteArrayOutputStream();

          @Override
          public boolean processBytes(byte[] buffer, int offset, int length) throws IOException {
            if (length >= 0) {
              out.write(buffer, offset, length);
            }
            return true;
          }

    }

    @SuppressWarnings("CheckReturnValue") // it doesn't matter what processBytes returns here
    @Override
    @ParametricNullness
    public <T extends @Nullable Object> T read(ByteProcessor<T> processor) throws IOException {
      processor.processBytes(bytes, offset, length);
      return processor.getResult();
    }

    @Override

    checkNotNull(input);
    checkNotNull(processor);

    byte[] buf = createBuffer();
    int read;
    do {
      read = input.read(buf);
    } while (read != -1 && processor.processBytes(buf, 0, read));
    return processor.getResult();
  }

  /**
   * Reads some bytes from an input stream and stores them into the buffer array {@code b}. This