display.refresh() hangs infinitely

Hey!

I'm using an e-ink display that is supported by this library. I've checked and call to `display.refresh()` stops and paused forever.

Do you have any clue what could be wrong?

Here is my code:

```python
import time
import board
import displayio
import adafruit_ssd1680

displayio.release_displays()

# This pinout works on a Metro M4 and may need to be altered for other boards.
spi = board.SPI() # Uses SCK and MOSI
epd_cs = board.D41
epd_dc = board.D40
epd_reset = board.D39 # Set to None for FeatherWing
epd_busy = board.D42 # Set to None for FeatherWing

print("1")

display_bus = displayio.FourWire(
spi, command=epd_dc, chip_select=epd_cs, reset=epd_reset, baudrate=1000000
)

print("2")
time.sleep(1)

# For issues with display not updating top/bottom rows correctly set colstart to 8
display = adafruit_ssd1680.SSD1680(
display_bus,
colstart=8,
width=250,
height=122,
busy_pin=epd_busy,
highlight_color=0xFF0000,
rotation=270,
)

print("3")

g = displayio.Group()

print("4")

with open("/display-ruler.bmp", "rb") as f:
pic = displayio.OnDiskBitmap(f)

print("5")

# CircuitPython 6 & 7 compatible
t = displayio.TileGrid(
pic, pixel_shader=getattr(pic, "pixel_shader", displayio.ColorConverter())
)

print("6")

# CircuitPython 7 compatible only
# t = displayio.TileGrid(pic, pixel_shader=pic.pixel_shader)
g.append(t)

print("7")

display.show(g)

print("8")

display.refresh()

print("refreshed")

time.sleep(120)

```

Start by running the provided CircuitPython script and comparing the printed markers around display.refresh(). Inspect the adafruit_ssd1680.SSD1680 refresh path, including the configured busy_pin. Done means determining why refresh() never returns and documenting or implementing a verified resolution.

Written by the indexing model from the issue text.