Pass file contents to plugin

I have this ios ionic/capacitor app, in one phase i see that the firmware on our hardware is out of date, and want to process an upgrade. the existing firmware has ble services to do this… start/stop/write and ack/nack

I have a ble plugin that does search and read/write characteristics using direct IOS ble api calls.
SO, I think the thruput would be better if I can pass the new file down to the plugin…(vs using the ble plugin) but it seems I have to use a dictionary for api calls, and don’t see a byte stream datatype, or maybe i’m just confused.
I haven’t tried yet… asking while thinking.

upload via OS bash script and python gets 12-13k/sec, over a meg data file.
a future enhancement is to broadcast the data to multiple devices concurrently… (as 50 times 1 minute is a long time waiting)…

have no wifi available… altho the hardware COULD become an access point