Expand description
The axum layer: extractors in, dispatch out.
No behavior lives here. Each handler resolves the request context once, names the route it
matched, and dispatches. /batch reaches the same dispatcher with the same context, which is
what keeps a sub-request and a top-level request from being two implementations.
The method override is dispatched explicitly rather than rewritten by middleware. The
JavaScript SDK sends every request as a POST with the real method in _method, and axum
matches on the transport method before a Router::layer runs. Verified by observation: a POST
carrying _method: "PUT" produced a 405 no matter where the layer was attached. So the
intended method travels in an extension and is read here. See body_credentials.