High CPU usage with BLEUART

[darkcurrent]

There is high CPU usage observed when reading bytes from BLEUART connection. With modified (bigger) buffer size in adafruit_ble/services/nordic.py, if I read 180 bytes of BLE buffer in about 50 times per second, that uses the total CPU about 20%-25% with RaspberryPi4. RPi4 has 4 cores so that means it uses the single core about 80% to 100% percent.

Current configuration:

Raspberry Pi OS: 5.4.72-v7l+
Adafruit_CircuitPython_BLE: 7.3.1
Adafruit_Blinka_bleio: 2.0.4
Bluez: 5.50-1.2~deb10u1+rpt2