Module tower 

tower middleware that records a span per request, built on the span module.

Behind the tower cargo feature. tower middleware that instruments each request future with a span.

Requires the tower feature.

Structs

Dial9SpanLayer

A tower::Layer that wraps a service so each request’s response future is recorded as a span.

Dial9SpanLayerWithResponse

A Layer like Dial9SpanLayer, but whose make_span closure also returns a finish callback for recording response-derived late fields.

Dial9SpanService

The Service produced by Dial9SpanLayer. Instruments each call’s future with a freshly-created span.

Dial9SpanServiceWithResponse

The Service produced by Dial9SpanLayerWithResponse.

OnResponse

Runs a callback with the successful response the moment the inner future resolves — before the enclosing Instrumented span emits its completion event, so late fields set by the callback ride that event. Constructed by Dial9SpanServiceWithResponse; not built directly.