Add locking to DummyFileManager

Author: dschwoerer

xarray/backends/file_manager.py

@@ -453,9 +453,13 @@ def _remove_del_methods():
 class DummyFileManager(FileManager[T_File]):
     """FileManager that simply wraps an open file in the FileManager interface."""
 
-    def __init__(self, value: T_File, *, close: Callable[[], None] | None = None):
+    def __init__(
+        self, value: T_File, *, close: Callable[[], None] | None = None
+        lock: Lock | None | Literal[False] = None,
+    ):
         if close is None:
             close = value.close
+        self._lock = lock
         self._value = value
         self._close = close
 
@@ -469,5 +473,8 @@ def acquire_context(self, needs_lock: bool = True) -> Iterator[T_File]:
         yield self._value
 
     def close(self, needs_lock: bool = True) -> None:
-        del needs_lock  # unused
-        self._close()
+        if needs_lock and self._lock:
+            with self._lock:
+                self._close()
+        else:
+            self._close()