Dynamo frontend in-flight request gauge

prometheus_names.py explicitly flags this as a gauge with no _total suffix - 'This is a gauge metric (current state) that can go up and down, so no _total suffix'. Counted from the frontend handler across HTTP entry to response completion. A companion dynamo_frontend_active_requests exists and the source comment says it is 'clearer for what inflight_requests measures' - the two are distinct and a reader should not assume they are the same series. NVIDIA Dynamo main (ai-dynamo/dynamo), read 2026-10-05. IMPORTANT CONTEXT that changes how every record in this set reads: Dynamo is a serving framework that BRIDGES vendor engine registries rather than reimplementing them. components/src/dynamo/common/backend/metrics.py has engines call register_global_registry (default prometheus_client.REGISTRY) or register_engine_registry (a custom CollectorRegistry, e.g. SGLang's multiprocess one), and their vendor-prefixed series - vllm:, sglang:, trtllm_, lmcache: - appear on the SAME /metrics endpoint alongside Dynamo's own dynamo_* names. So on a Dynamo deployment you will find vLLM and SGLang metrics that are recorded in this repo against THOSE engines, and the dynamo_component / dynamo_namespace / dynamo_endpoint labels plus model and model_name are injected at scrape time by Dynamo. The names below are Dynamo's OWN, from the auto-generated prometheus_names.py (generated from lib/runtime/src/metrics/prometheus_names.rs - do not hand-edit). Prefix is dynamo_frontend.