Rhythm Events map onto the Event structure.
struct RhythmEvent {
struct RhythmEvent *next; /* The next event in the list. */
long time; /* When this event occurs. */
char type; /* What type of event. */
char pad; /* Empty. */
unsigned short rhythmid; /* Id of rhythm clip. */
struct Rhythm *rhythm; /* Rhythm. */
struct NoteEvent *point; /* Current position in rhythm. */
};