Missing elapsed time on a buffered HTTPX response?

Start with the simplest option

If you own a test fixture and only need a synthetic response to expose an elapsed value, set it directly when constructing the fixture:

from datetime import timedelta
import httpx

response = httpx.Response(200, content=b"fixture")
response.elapsed = timedelta(0)  # Timing unavailable, not latency.

See the existing zero-value fixture workaround. You do not need another wrapper just for this.

Use the downloaded wrapper when you need that policy at a custom transport boundary across multiple responses, in sync or async clients. It preserves an elapsed value already supplied by the transport and only adds a zero fallback when the value is missing on an already closed and consumed response.

The upstream review on preserving timings explains why existing values should survive. This wrapper does not measure network time, change streaming responses, or replace an upstream release.

The module exports BufferedElapsedTransport and AsyncBufferedElapsedTransport. Use ELAPSED_PLACEHOLDER_EXTENSION to identify the fallback marker in response.extensions; see the README for the exact check.

Run it locally

Extract the ZIP into a local folder. It contains httpx_buffered_elapsed.py, test_httpx_buffered_elapsed.py, README.md, and LICENSE.txt. The MIT license covers only these example files, not the company repository. Read the README for sync and async usage from the downloaded module.

Use your local Python environment, preferably a virtual environment. The example was tested against HTTPX 0.28.1; the tests also require pytest. If you are setting up an isolated test environment, install these dependencies there:

python -m pip install "httpx==0.28.1" pytest

From the extracted folder, run the offline demo and tests. Dependency installation needs package access; the demo itself does not make network requests.

python httpx_buffered_elapsed.py
python -m pytest test_httpx_buffered_elapsed.py -q

Review the code and run your own transport tests before using it. Compatibility beyond the tested Python and HTTPX versions has not been verified. Do not downgrade a working application just for this example.