midi packet list dose not change timestamp - ios

Question

i have this code from here(Using MIDIPacketList in swift) but i can't pm the user or comment on that question, so i will ask my question.
#ephemer dude if you see my question, i love your code on midi list and it work so well, but when i change the time stamp, nothing happens, it must create some delay but it will be the same as 0 time stamp.
do anyone know how to fix this?
and how i can have the time stamp out of this extension to have that in midi event, i want to be able to change time stamp for every midi event,
to have it here:
var packets = MIDIPacketList(midiEvents: [[0x90, 60, 100]])
public typealias MidiEvent = [UInt8]
extension MIDIPacketList {
init(midiEvents: [MidiEvent]) {
let timestamp = MIDITimeStamp(0) // do it now
let totalBytesInAllEvents = midiEvents.reduce(0) { total, event in
return total + event.count
}
// Without this, we'd run out of space for the last few MidiEvents
let listSize = MemoryLayout<MIDIPacketList>.size + totalBytesInAllEvents
// CoreMIDI supports up to 65536 bytes, but in practical tests it seems
// certain devices accept much less than that at a time. Unless you're
// turning on / off ALL notes at once, 256 bytes should be plenty.
assert(totalBytesInAllEvents < 256,
"The packet list was too long! Split your data into multiple lists.")
// Allocate space for a certain number of bytes
let byteBuffer = UnsafeMutablePointer<UInt8>.allocate(capacity: listSize)
// Use that space for our MIDIPacketList
self = byteBuffer.withMemoryRebound(to: MIDIPacketList.self, capacity: 1) { packetList -> MIDIPacketList in
var packet = MIDIPacketListInit(packetList)
midiEvents.forEach { event in
packet = MIDIPacketListAdd(packetList, listSize, packet, timestamp, event.count, event)
}
return packetList.pointee
}
byteBuffer.deallocate() // release the manually managed memory
}
}
// to send use this
var packets = MIDIPacketList(midiEvents: [[0x90, 60, 100]])
MIDISend(clientOutputPort, destination, &packetList)

Answer 1

i figure it out, how it should work, but not quite right.
according to apple documentation, it must use mach_absolute_time() .
so i used that but i don't know how to work properly with mach_absolute_time().if anyone knows please tell me too.
if i use var timestamp = mach_absolute_time()[phone] it will delay like 1 min or so.if i change the 1000000000 with any number lower than this ,will not make a delay.
do anyone know how to work with mach_absolute_time()?
i saw some code on mach_absolute_time() but they use that as timer, it is acutely a timer that give time from the fist boot ,but how to give a time as a mach_absolute_time() to work with midi timestamp.

Answer 2

I found the answer.
set the timestamp to :
var delay = 0.2
var timestamp: MIDITimeStamp = mach_absolute_time() + MIDITimeStamp(delay * 1_000_000_000)
the delay is the time you want the midi message age to have delay.