/* define a set of marker types that can be used to refer to set points in the
* mbuf */
+__extension__
typedef void *MARKER[0]; /**< generic marker for a point in a structure */
+__extension__
typedef uint8_t MARKER8[0]; /**< generic marker with 1B alignment */
+__extension__
typedef uint64_t MARKER64[0]; /**< marker that allows us to overwrite 8 bytes
* with a single assignment */