chore: import upstream snapshot with attribution

docs/code-docs/source/inference-engine.rst

@@ -0,0 +1,15 @@
+Inference API
+=============
+
+:func:`deepspeed.init_inference` returns an *inference engine*
+of type :class:`InferenceEngine`.
+
+.. code-block:: python
+
+    for step, batch in enumerate(data_loader):
+        #forward() method
+        loss = engine(batch)
+
+Forward Propagation
+-------------------
+.. autofunction:: deepspeed.InferenceEngine.forward