@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
final class MultiInputStream extends InputStream {

  private Iterator<? extends ByteSource> it;
  @CheckForNull private InputStream in;

  /**
   * Creates a new instance.
   *
   * @param it an iterator of I/O suppliers that will provide each substream
   */
  public MultiInputStream(Iterator<? extends ByteSource> it) throws IOException {
    this.it = checkNotNull(it);

    assertEquals(20, total);
  }

  @SuppressWarnings("CheckReturnValue") // these calls to skip always return 0
  public void testSkip() throws Exception {
    MultiInputStream multi =
        new MultiInputStream(
            Collections.singleton(
                    new ByteSource() {
                      @Override
                      public InputStream openStream() {

    assertEquals(20, total);
  }

  @SuppressWarnings("CheckReturnValue") // these calls to skip always return 0
  public void testSkip() throws Exception {
    MultiInputStream multi =
        new MultiInputStream(
            Collections.singleton(
                    new ByteSource() {
                      @Override
                      public InputStream openStream() {