protected String objectToString(Object o) {
        return o.toString();
    }
Default implementation merely returns <code>objectArgument.toString()</code>.  Subclasses can override this
method for different mechanisms of converting an object to a String.

@param o the Object to convert to a byte array.
@return a String representation of the Object argument.
src/main/java/org/apache/shiro/lang/codec/CodecSupport.java