The relative timestamp within the source measure.
States whether the VoiceEntry has (only) grace notes.
States whether the grace note(s) have a slash (Acciaccatura, played before the beat)
Moves the voice entry to another staff entry, e.g. grace notes after their main note into the main note's staff entry (InstrumentReader.attachGraceNotesAfterMainNote). Also re-parents its notes. Doesn't change the staff entries' VoiceEntries lists.
Staticis
A [[VoiceEntry]] contains the notes in a voice at a timestamp.