chore: add blob experimental flag (#1150)

* chore: add blob experimental flag

* revert notebook

Author: GarrettWu

bigframes/_config/experiment_options.py

@@ -22,6 +22,7 @@ class ExperimentOptions:
 
     def __init__(self):
         self._semantic_operators = False
+        self._blob = False
 
     @property
     def semantic_operators(self) -> bool:
@@ -34,3 +35,15 @@ def semantic_operators(self, value: bool):
                 "Semantic operators are still under experiments, and are subject to change in the future."
             )
         self._semantic_operators = value
+
+    @property
+    def blob(self) -> bool:
+        return self._blob
+
+    @blob.setter
+    def blob(self, value: bool):
+        if value is True:
+            warnings.warn(
+                "BigFrames Blob is still under experiments. It may not work and subject to change in the future."
+            )
+        self._blob = value

tests/unit/_config/test_experiment_options.py

@@ -30,3 +30,18 @@ def test_semantic_operators_set_true_shows_warning():
         options.semantic_operators = True
 
     assert options.semantic_operators is True
+
+
+def test_blob_default_false():
+    options = experiment_options.ExperimentOptions()
+
+    assert options.blob is False
+
+
+def test_blob_set_true_shows_warning():
+    options = experiment_options.ExperimentOptions()
+
+    with pytest.warns(UserWarning):
+        options.blob = True
+
+    assert options.blob is True