Function write_midi 

pub fn write_midi(
    notes: &NoteList,
    bpm: Bpm,
    velocities: Velocities,
) -> Result<Vec<u8>, MidiWriteError>

Encodes the notes as a format 0 file at a BPM.

Times become ticks with round(seconds * BPM / 60 * 480), so each lies within half a tick of the note. The tempo event at tick 0 holds round(60,000,000 / BPM) microseconds per beat. A fractional pitch rounds to the nearest key. Three rules any player needs come first: a note shorter than MIN_NOTE_LENGTH or one tick is lengthened, of two notes with one key and one start only the longer stays, and a note that still sounds when its key starts again ends there. At one tick a note-off comes before a note-on, so two touching notes of one pitch stay two. The file has no program change and no pitch bend.

Errors

Returns a MidiWriteError for an empty list, which no reader of ours accepts, and when two events lie further apart than a MIDI delta time holds, about nine hours at 1000 BPM.