(Feat) Add x-litellm-overhead-duration-ms and "x-litellm-response-duration-ms" in response from LiteLLM (#7899)

* add track_llm_api_timing

* add track_llm_api_timing

* test_litellm_overhead

* use ResponseMetadata class for setting hidden params and response overhead

* instrument http handler

* fix track_llm_api_timing

* track_llm_api_timing

* emit response overhead on hidden params

* fix resp metadata

* fix make_sync_openai_embedding_request

* test_aaaaatext_completion_endpoint fixes

* _get_value_from_hidden_params

* set_hidden_params

* test_litellm_overhead

* test_litellm_overhead

* test_litellm_overhead

* fix import

* test_litellm_overhead_stream

* add LiteLLMLoggingObject

* use diff folder for testing

* use diff folder for overhead testing

* test litellm overhead

* use typing

* clear typing

* test_litellm_overhead

* fix async_streaming

* update_response_metadata

* move test file

* pply metadata to the response objec

tests/litellm_utils_tests/conftest.py

@@ -0,0 +1,54 @@
+# conftest.py
+
+import importlib
+import os
+import sys
+
+import pytest
+
+sys.path.insert(
+    0, os.path.abspath("../..")
+)  # Adds the parent directory to the system path
+import litellm
+
+
+@pytest.fixture(scope="function", autouse=True)
+def setup_and_teardown():
+    """
+    This fixture reloads litellm before every function. To speed up testing by removing callbacks being chained.
+    """
+    curr_dir = os.getcwd()  # Get the current working directory
+    sys.path.insert(
+        0, os.path.abspath("../..")
+    )  # Adds the project directory to the system path
+
+    import litellm
+    from litellm import Router
+
+    importlib.reload(litellm)
+    import asyncio
+
+    loop = asyncio.get_event_loop_policy().new_event_loop()
+    asyncio.set_event_loop(loop)
+    print(litellm)
+    # from litellm import Router, completion, aembedding, acompletion, embedding
+    yield
+
+    # Teardown code (executes after the yield point)
+    loop.close()  # Close the loop created earlier
+    asyncio.set_event_loop(None)  # Remove the reference to the loop
+
+
+def pytest_collection_modifyitems(config, items):
+    # Separate tests in 'test_amazing_proxy_custom_logger.py' and other tests
+    custom_logger_tests = [
+        item for item in items if "custom_logger" in item.parent.name
+    ]
+    other_tests = [item for item in items if "custom_logger" not in item.parent.name]
+
+    # Sort tests based on their names
+    custom_logger_tests.sort(key=lambda x: x.name)
+    other_tests.sort(key=lambda x: x.name)
+
+    # Reorder the items list
+    items[:] = custom_logger_tests + other_tests