Android : How to create Parcelable code for GregorianCalendar

I haven't understood how to create the code needed to implement correctly the Parcelable for an object that contains GregorianCalendar objects.

E.g. fot an object User that contains String name; and GregorianCalendar creationDate;, my attempt is this:

 @Override
    public int describeContents() {
        return 0;
    }

@Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeString(this.name);
        dest.writeParcelable(this.creationDate, flags);
    }

    private User(Parcel in) {
        this.name = in.readString();
        this.creationDate = in.readParcelable(GregorianCalendar.class.getClassLoader());
    }

    public static final Creator<User> CREATOR = new Creator<User>() {
        public User createFromParcel(Parcel source) {
            return new User(source);
        }

        public User[] newArray(int size) {
            return new User[size];
        }
    };

that unfortunately doesn't work

in writeToParcel() at the line

dest.writeParcelable(this.creationDate, flags);

get writeParcelable cannot be applied to GregorianCalendar error

in

this.creationDate = in.readParcelable(GregorianCalendar.class.getClassLoader());

get Incompatible types error

How to code correctly the Parcelable?