Deprecation warning for fieldfilebuffer

parcels/fieldfilebuffer.py

@@ -0,0 +1,13 @@
+import warnings
+
+from parcels._fieldfilebuffer import DaskFileBuffer, DeferredDaskFileBuffer, NetcdfFileBuffer, _FileBuffer
+
+__all__ = ["DaskFileBuffer", "DeferredDaskFileBuffer", "NetcdfFileBuffer", "_FileBuffer"]
+
+warnings.warn(
+    "The `parcels.fieldfilebuffer` module is deprecated as it has been marked private. "
+    "Users are not expected to use it in their scripts. See https://github.com/OceanParcels/Parcels/issues/1773 "
+    "to continue discussion.",
+    DeprecationWarning,
+    stacklevel=2,
+)  # TODO: Remove 6 months after v3.1.1

tests/test_deprecations.py

@@ -411,3 +411,13 @@ def test_removed_attrib(removed_attribute_action: Action):
 
     with pytest.raises(AttributeError):
         getattr(obj, action.public_name)
+
+
+def test_private_fieldfilebuffer():
+    with pytest.warns(DeprecationWarning):
+        from parcels.fieldfilebuffer import (  # noqa: F401
+            DaskFileBuffer,
+            DeferredDaskFileBuffer,
+            NetcdfFileBuffer,
+            _FileBuffer,
+        )