incoming MIDI notifications not aligned with hcidump

[evanraalte]

Hi! First of all thank you for developing this library. I am having a lot of fun with it, while interfacing with my piano over BLE :)

There is an issue I am experiencing while handling notifications (in my case midi BLE messages). In my HCI snoop log, I receive every message exactly when I expect it. In this case (just to put it in context):

• Six midi notes ON when I press six keys at once (time = 20:12:39)
• Six midi notes OFF when I release the keys at once (time = 20:12:48)
• One midi note ON when I press a single key (time = 20:12:55.67)
• One midi note OFF when I release the single key (time = 20:12:55.73)

However, my delegate class has some issues printing everything at the expected time (eventually it receives everything). This is the handler I used for generating the data right now:

def handleNotification(self, cHandle, data):
        log.debug(f"raw data: {data.hex()}")

The notifications are here as follows:

• 4 midi notes ON (time = 20:12:39) -> I expect 6 notes
• 2 midi notes ON, 3 midi notes off (time = 20:12:48) -> got the remainder of the messages that should have been propagated 10 seconds ago, and only four of the six messages that indicate a key has been released.
• 3 midi notes OFF, 1 midi note ON (time = 20:12:55.67) -> remainder of the keys that should have turned of is received here. single note that was pressed is received as expected.
• 1 midi note off (time = 20:12:55.73) -> Release of key, exactly as I expected.

I did not find any configuration option for minimizing / bundling / flushing messages. So I thought it might be something that is worth looking at?

If you think that I missed to provide some information on the logs, here is a side by side view of hcidump and my delegate handler.

Also, please let me know if there is any other important information lacking in this issue :)

Erik