granian 1.7.0 breaks compatiblity with starlette/fastapi if middlewares applied

[jvllmr]

After upgrading to granian 1.7.0 I receive the following upon the first request:

jan@NB1700 ~/d/tooltime (0.5.x)> granian --interface asgi tooltime.wsgi:app
[INFO] Starting granian (main PID: 8519)
[INFO] Listening at: http://127.0.0.1:8000
[INFO] Spawning worker-1 with pid: 8520
[INFO] Started worker-1
[INFO] Started worker-1 runtime-1
[ERROR] Application callable raised an exception
Traceback (most recent call last):
  File "/home/jan/dev/tooltime/.venv/lib/python3.12/site-packages/granian/_futures.py", line 11, in future_watcher
    await inner(watcher.scope, watcher.proto)
  File "/home/jan/dev/tooltime/.venv/lib/python3.12/site-packages/fastapi/applications.py", line 1054, in __call__
    await super().__call__(scope, receive, send)
  File "/home/jan/dev/tooltime/.venv/lib/python3.12/site-packages/starlette/applications.py", line 113, in __call__
    await self.middleware_stack(scope, receive, send)
  File "/home/jan/dev/tooltime/.venv/lib/python3.12/site-packages/starlette/middleware/errors.py", line 187, in __call__
    raise exc
  File "/home/jan/dev/tooltime/.venv/lib/python3.12/site-packages/starlette/middleware/errors.py", line 165, in __call__
    await self.app(scope, receive, _send)
  File "/home/jan/dev/tooltime/.venv/lib/python3.12/site-packages/uvicorn/middleware/proxy_headers.py", line 60, in __call__
    return await self.app(scope, receive, send)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/jan/dev/tooltime/.venv/lib/python3.12/site-packages/starlette/middleware/base.py", line 186, in __call__
    async with anyio.create_task_group() as task_group:
  File "/home/jan/dev/tooltime/.venv/lib/python3.12/site-packages/anyio/_backends/_asyncio.py", line 772, in __aenter__
    self.cancel_scope.__enter__()
  File "/home/jan/dev/tooltime/.venv/lib/python3.12/site-packages/anyio/_backends/_asyncio.py", line 425, in __enter__
    task_state = _task_states[host_task]
                 ~~~~~~~~~~~~^^^^^^^^^^^
  File "/home/jan/dev/tooltime/.venv/lib/python3.12/site-packages/anyio/_backends/_asyncio.py", line 686, in __getitem__
    assert isinstance(key, asyncio.Task)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 

The error does not occur when downgrading granian to 1.6.4 or removing all my middlewares.

I have the following middlewares:

app.add_middleware(BaseHTTPMiddleware, dispatch=exception_middleware)
app.add_middleware(BaseHTTPMiddleware, dispatch=file_middleware)
app.add_middleware(ProxyHeadersMiddleware, trusted_hosts=current_config.trusted_hosts)

where ProxyHeadersMiddleware comes from uvicorn.

[gi0baro]

@jvllmr can you try with #468 ?

[jvllmr]

I have tested the PR in the same codebase and the issue seems to be fixed.