Implement get on CaseInsensitiveDict

get was previously provided by the parent class which
had to raise KeyError for missing values. Since try/except
is only cheap for the non-exception case the performance
was not good when the key was missing

similar to python/cpython#106665
but in the HA case we call this even more frequently

async_upnp_client/utils.py

@@ -56,6 +56,18 @@ def replace(self, new_data: abcMapping) -> None:
             self._data = {**new_data}
         self._case_map = {k.lower(): k for k in self._data}
 
+    def get(self, key: str, default: Any = None) -> Any:
+        """Get item with default.
+
+        This implementation is case insensitive and avoids
+        calling __getitem__ which would raise KeyError and
+        cause unnecessary exception handling.
+        """
+        data_key = self._case_map.get(key.lower(), _SENTINEL)
+        if data_key is not _SENTINEL:
+            return self._data.get(data_key, default)
+        return default
+
     def __setitem__(self, key: str, value: Any) -> None:
         """Set item."""
         lower_key = key.lower()