public List<EncodingDetector> getDetectors() {
        return Collections.unmodifiableList(detectors);
    }
@param input    text document input stream, or <code>null</code>
@param metadata input metadata for the document
@return the detected Charset or null if no charset could be detected
@throws IOException
tika-core/src/main/java/org/apache/tika/detect/CompositeEncodingDetector.java