@SuppressWarnings("unchecked")
    public <T> T option(BoltOption<T> option) {
        Object value = options.get(option);
        if (value == null) {
            value = option.defaultValue();
        }

        return value == null ? null : (T) value;
    }
Get the optioned value.
Return default value if option does not exist.

@param option target option
@return the optioned value of default value if option does not exist.
src/main/java/com/alipay/remoting/config/BoltOptions.java