Arvados

This is a little inconvenient because the queue decision happens lower in the handler stack than the inspector (and we don't want to change that).

We can do something similar to responseLogFieldsContextKey in source:sdk/go/httpserver/logger.go -- attach an atomic.Value to the request context as it passes through the Inspect handler, then have RequestLimiter Store() queue status there (queue label, time the request was released for processing), and Load() when generating the _inspect/requests report.