bundles/org.tukani.xz/src/org/tukaani/xz/SingleXZInputStream.java
private static byte[] readStreamHeader(InputStream in) throws IOException {
        byte[] streamHeader = new byte[DecoderUtil.STREAM_HEADER_SIZE];
        new DataInputStream(in).readFully(streamHeader);
        return streamHeader;
    }
private static byte[] readStreamHeader(InputStream in) throws IOException {
        byte[] streamHeader = new byte[DecoderUtil.STREAM_HEADER_SIZE];
        new DataInputStream(in).readFully(streamHeader);
        return streamHeader;
    }
Reads the Stream Header into a buffer.
This is a helper function for the constructors.