@Override
    public void write(DocumentType type) {
        byte[] docType = createUTF8CharArray(type.getName());
        put(null, docType);
        putByte(null, ((byte) 0));
        putShort(null, (short) 0); // Used to hold the version. Is now always 0.
    }
Write out the value of weighted set field

@param field - field description (name and data type)
@param ws    - field value
document/src/main/java/com/yahoo/document/serialization/VespaDocumentSerializer6.java