Add locking to DummyFileManager

Author: dschwoerer

xarray/backends/file_manager.py

@@ -344,9 +344,16 @@ def __hash__(self):
 class DummyFileManager(FileManager):
     """FileManager that simply wraps an open file in the FileManager interface."""
 
-    def __init__(self, value, *, close=None):
+    def __init__(
+        self,
+        value,
+        *,
+        close=None,
+        lock: Lock | None | Literal[False] = None,
+    ):
         if close is None:
             close = value.close
+        self._lock = lock
         self._value = value
         self._close = close
 
@@ -360,5 +367,8 @@ def acquire_context(self, needs_lock=True):
         yield self._value
 
     def close(self, needs_lock=True):
-        del needs_lock  # ignored
-        self._close()
+        if needs_lock and self._lock:
+            with self._lock:
+                self._close()
+        else:
+            self._close()