Detect blocking module imports in the event loop (#114488)

homeassistant/bootstrap.py

@@ -23,7 +23,14 @@ import cryptography.hazmat.backends.openssl.backend  # noqa: F401
 import voluptuous as vol
 import yarl
 
-from . import config as conf_util, config_entries, core, loader, requirements
+from . import (
+    block_async_io,
+    config as conf_util,
+    config_entries,
+    core,
+    loader,
+    requirements,
+)
 
 # Pre-import frontend deps which have no requirements here to avoid
 # loading them at run time and blocking the event loop. We do this ahead
@@ -260,6 +267,8 @@ async def async_setup_hass(
     _LOGGER.info("Config directory: %s", runtime_config.config_dir)
 
     loader.async_setup(hass)
+    block_async_io.enable()
+
     config_dict = None
     basic_setup_success = False