chore: import upstream snapshot with attribution

deepspeed/runtime/checkpoint_engine/README.md

@@ -0,0 +1,37 @@
+# Checkpoint Engine
+
+
+The `CheckpointEngine` was designed to modularized the checkpoint serialization. In this way, we can simply replace/refine the checkpoint serialization methods.
+
+### Interface for `CheckpointEngine`
+
+Basically, for checkpoint management(save/load by deepspeed with the given tag), the `CheckpointEngine` will:
+
+	1. To make preliminaries ready by call `create(tag)`. For `torch`, we can just log some extra info as `torch` can directly call `save/load` without other preparation.
+
+	2. After the `create(tag)`, deepspeed can call `save/load` to persist files into disk/memory/etc.
+
+	3. When all the files for a tag are ready, deepspeed engine will call `commit()` to tell the checkpoint engine current checkpoint is complete. For original torch, it also plays the role of logger.
+
+
+```python
+class CheckpointEngine(object):
+    # init checkpoint engine for save/load
+    def __init__(self, config_params=None):
+        pass
+
+    def create(self, info:CheckpointCommitInfo):
+        # create checkpoint on give tag for save/load.
+        pass
+
+    def save(self, state_dict, path: str):
+        pass
+
+    def load(self, path: str, map_location=None):
+        pass
+
+    def commit(self, info:CheckpointCommitInfo):
+        # to tell checkpoint services if all files are readys.
+        pass
+
+```