4.112.0 - Adds Support for Tracing Header Extraction

What's Changed

Adds Support for Tracing Header Extraction by @NeedleInAJayStack in #3280

This adds header extraction support for tracing backends as described in this document. In the context of OTEL, this is used to correlate trace data across the HTTP boundary by passing the traceparent and tracestate header, as documented here and implemented in the swift-otel package here.

It also adds a closure to TracingMiddleware that allows users to set custom span metadata on requests.

Finally, it fixes a few warnings caused by the MiddlewareTest function introduced in vapor/vapor#3253

This patch was released by @0xTim

Full Changelog: 4.111.1...4.112.0