public Postcard withParcelable(@Nullable String key, @Nullable Parcelable value) {
        mBundle.putParcelable(key, value);
        return this;
    }
public Postcard withParcelable ( @ Nullable String key , @ Nullable Parcelable value ) { mBundle . putParcelable ( key , value ) ; return this ; }
Inserts a Parcelable value into the mapping of this Bundle, replacing
any existing value for the given key.  Either key or value may be null.

@param key   a String, or null
@param value a Parcelable object, or null
@return current