describe
Describe the kinds of special objects contained in this Parcelable instance's marshaled representation. For example, if the object will include a file descriptor in the output of {@link #writeToParcel(Parcel, int)}, the return value of this method must include the {@link #CONTENTS_FILE_DESCRIPTOR} bit.
Return
a bitmask indicating the set of special object types marshaled by this Parcelable object instance.