Create midi event for lilv

LV2_Atom_Sequence seq = {
    { sizeof(LV2_Atom_Sequence_Body),
      map.map(map.handle, LV2_ATOM__Sequence) },
    { 0, 0 } };

typedef struct {
    LV2_Atom_Event event;
    uint8_t        msg[3];
} MIDINoteEvent;


lilv_instance_connect_port(instance, 0, &seq);


// Clear sequence and add new midi event.
lv2_atom_sequence_clear(&seq);

uint8_t key = 1;
int8_t velocity = 127;
const char buffer[] = { 0x90, key, velocity };
const uint32_t out_capacity = seq.atom.size;

MIDINoteEvent ev;
ev.event.time.frames = 5;// frame time (samplecount?)
ev.event.body.type   = map.map(map.handle, LV2_MIDI__MidiEvent);
ev.event.body.size   = sizeof(MIDINoteEvent);

ev.msg[0] = buffer[0];
ev.msg[1] = buffer[1];
ev.msg[2] = buffer[2];

lv2_atom_sequence_append_event(&seq, out_capacity, &ev.event);

lilv_instance_run(instance, 10);