@SuppressWarnings("unchecked")
    public <V> V getExtraOption(java.lang.String key)
    {
        return (V) extraOptions.get(key);
    }
Represents the message defined in the {@link Proto}.

@author David Yu
@created Dec 19, 2009
protostuff-parser/src/main/java/io/protostuff/parser/Message.java