reader.setScrollSize(1000);
        int count = 0;
        Set<String> valueSet = Collections.synchronizedSet(new HashSet<>());
        Map<String, Object> source;
        while ((source = reader.read()) != null) {
            assertTrue(source.get("field1").toString().startsWith("test"));
            valueSet.add(source.get("field1").toString());
            count++;
        }
        assertEquals(num, count);

    // The stream reports no bytes... importantly, it doesn't read the byte at index 5 when it
    // should be reading the byte at index 10.
    // We could use a custom InputStream instead to make the read start at index 10, but since this
    // is a racy situation anyway, this behavior seems reasonable.
    assertEquals(-1, in.read());
  }

  private static class AppendableByteSource extends ByteSource {

    @Override
    public Settings read(File input, Map<String, ?> options) throws IOException {
        Objects.requireNonNull(input, "input cannot be null");

        try (InputStream in = Files.newInputStream(input.toPath())) {
            InputSource source = new InputSource(input.toString());
            return new Settings(new SettingsStaxReader().read(in, isStrict(options), source));

		panic("Failed to acquire read lock")
	}
	// fmt.Println("1st read lock acquired, waiting...")

	if !lrwm.GetRLock(ctx, "", "object1", time.Second) {
		panic("Failed to acquire read lock")
	}
	// fmt.Println("2nd read lock acquired, waiting...")

	go func() {
		time.Sleep(2 * time.Second)
		lrwm.RUnlock()
		// fmt.Println("1st read lock released, waiting...")
	}()

	go func() {

	switch rval := result.(type) {
	case string:
		return FromString(rval), nil
	case float64:
		return FromFloat(rval), nil
	case int64:
		return FromInt(rval), nil
	case uint64:
		if rval <= math.MaxInt64 {
			return FromInt(int64(rval)), nil
		}
		return FromFloat(float64(rval)), nil
	case bool:
		return FromBool(rval), nil
	case jstream.KVS:

            final ExpressionEvaluator evaluator,
            final ClassRealm realm,
            final ConfigurationListener listener)
            throws ComponentConfigurationException {
        try {
            ClassRealmConverter.pushContextRealm(realm);

            this.configureComponent(component, configuration, evaluator, (ClassLoader) realm, listener);
        } finally {
            ClassRealmConverter.popContextRealm();

        int ftag = in.read();
        int tag = readTagNumber(in, ftag);
        if ( tag != expectTag ) {
            throw new IOException("Unexpected tag " + tag);
        }
        int length = readLength(in, limit, false);
        byte[] content = new byte[length];
        in.read(content);
        return content;
    }

	closed   bool
}

func (pr *progressReader) Read(p []byte) (n int, err error) {
	// This ensures that Close will block until Read has completed.
	// This allows another goroutine to close the reader.
	pr.closedMu.Lock()
	defer pr.closedMu.Unlock()
	if pr.closed {
		return 0, errors.New("progressReader: read after Close")
	}
	return pr.processedReader.Read(p)
}

func (pr *progressReader) Close() error {

    @Override
    public PersistedToolchains read(File input, Map<String, ?> options) throws IOException {
        Objects.requireNonNull(input, "input cannot be null");

        try (InputStream in = Files.newInputStream(input.toPath())) {
            InputSource source = new InputSource(input.toString());
            return new PersistedToolchains(new MavenToolchainsStaxReader().read(in, isStrict(options), source));

	// check not at EOF
	b.WriteString("abcdefghijklmnopqrstuvwxyz")

	// after unsuccessful read
	if n, err := b.Read(nil); n != 0 || err != nil {
		t.Fatalf("Read(nil) = %d,%v; want 0,nil", n, err)
	}
	if err := b.UnreadByte(); err == nil {
		t.Fatal("UnreadByte after Read(nil): got no error")
	}

	// after successful read
	if _, err := b.ReadBytes('m'); err != nil {
		t.Fatalf("ReadBytes: %v", err)
	}