Module observability 

Available on crate feature serve only.

serve-owned observability: install the Prometheus recorder (returning a render handle for the /metrics route) and a tracing subscriber whose fmt layer routes through the secret-redacting writer and whose RunLogLayer feeds the per-run SSE log buffers. Both are process-global and set-once; a second install in the same process is tolerated (returns no handle / leaves the existing subscriber). The returned LogHub is shared with ServerState so the /logs handler reads the same buffers the layer writes.

Functions

install

Install the recorder + tracing subscriber. Returns the Prometheus render handle (when this call installed the recorder; None if one was already present) and the process-global LogHub wired into the subscriber’s RunLogLayer.