public ByteArrayBuilder append(final char[] b, final int off, final int len) {
        if (b == null) {
            return this;
        }
        if (off < 0 || off > b.length || len < 0 ||
                off + len < 0 || off + len > b.length) {
            throw new IndexOutOfBoundsException("off: " + off + " len: " + len + " b.length: " + b.length);
        }
        return append(CharBuffer.wrap(b, off, len));
    }
Builder class for sequences of bytes.

@since 5.0
httpclient5/src/main/java/org/apache/hc/client5/http/utils/ByteArrayBuilder.java